US9060820B2 - Segmented intramedullary fracture fixation devices and methods - Google Patents

Abstract

A segmented bone fixation device is provided with an elongate body having a longitudinal axis and having a first state in which at least a portion of the body is flexible and a second state in which the body is generally rigid. Methods of repairing a fracture of a bone are also disclosed. One such method comprises inserting a segmented fixation device into an intramedullary space of the bone to place at least a portion of the fixation device in a flexible state on one side of the fracture, providing rigidity across the fracture, and operating an actuator to deploy at least one gripper to engage an inner surface of the intramedullary space to anchor the fixation device to the bone. Various configurations allow a segmented device body to change shape as it moves from a flexible state to a rigid state.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. Provisional Application 61/553,062, titled “SEGMENTED INTRAMEDULLARY FRACTURE FIXATION DEVICES AND METHODS”, filed Oct. 28, 2011, which is incorporated by reference in its entirety herein.

This application is a Continuation-in-Part of U.S. application Ser. No. 12/482,388, filed Jun. 10, 2009, which claims the benefit of priority of U.S. Provisional Applications: No. 61/060,440, filed Jun. 10, 2008; No. 61/060,445, filed Jun. 10, 2008; No. 61/060,450, filed Jun. 10, 2008; No. 61/100,635, filed Sep. 26, 2008; No. 61/100,652, filed Sep. 26, 2008; No. 61/117,901, filed Nov. 25, 2008; No. 61/122,563, filed Dec. 15, 2008; and No. 61/138,920, filed Dec. 18, 2008. U.S. application Ser. No. 12/482,388 is also a Continuation-in-Part of U.S. application Ser. No. 11/383,269, filed May 15, 2006 which claims the benefit of priority of U.S. Provisional Application No. 60/682,652, filed May 18, 2005. U.S. application Ser. No. 12/482,388 is also a Continuation-in-part of U.S. application Ser. No. 11/383,800 filed May 17, 2006, which claims the benefit of priority of U.S. Provisional Application No. 60/682,652, filed May 18, 2005. U.S. application Ser. No. 12/482,388 is also a Continuation-in-Part of U.S. application Ser. No. 11/944,366, filed Nov. 21, 2007 which claims the benefit of priority of U.S. Provisional Applications: No. 60/867,011, filed Nov. 22, 2006; No. 60/866,976, filed Nov. 22, 2006; and No. 60/949,071, filed Jul. 11, 2007: all of which are incorporated by reference in their entireties herein.

This application is a Continuation-in-Part of U.S. application Ser. No. 12/482,406, filed Jun. 10, 2009. U.S. application Ser. No. 12/482,406 claims the benefit of priority of U.S. Provisional Applications: No. 61/060,440, filed Jun. 10, 2008; No. 61/060,445, filed Jun. 10, 2008; No. 61/060,450, filed Jun. 10, 2008; No. 61/100,635, filed Sep. 26, 2008; No. 61/100,652, filed Sep. 26, 2008; No. 61/117,901, filed Nov. 25, 2008; No. 61/122,563, filed Dec. 15, 2008; and No. 61/138,920, filed Dec. 18, 2008. U.S. application Ser. No. 12/482,406 is also a Continuation-in-Part of U.S. application Ser. No. 11/383,269, filed May 15, 2006 which claims the benefit of priority of U.S. Provisional Application No. 60/682,652, filed May 18, 2005. U.S. application Ser. No. 12/482,406 is also a Continuation-in-part of U.S. application Ser. No. 11/383,800, filed May 17, 2006, which claims the benefit of priority of U.S. Provisional Application No. 60/682,652, filed May 18, 2005. U.S. application Ser. No. 12/482,406 is also a Continuation-in-Part of U.S. application Ser. No. 11/944,366, filed Nov. 21, 2007 which claims the benefit of priority of U.S. provisional applications: No. 60/867,011, filed Nov. 22, 2006; No. 60/866,976, filed Nov. 22, 2006; and No. 60/949,071, filed Jul. 11, 2007: all of which are incorporated by reference in their entireties herein.

This application is a Continuation-in-Part of U.S. application Ser. No. 12/642,648, filed Aug. 26, 2011 which claims the benefit of priority of U.S. Provisional Application No. 61/138,920, filed Dec. 18, 2008: all of which are incorporated by reference in their entireties herein.

This application is a Continuation-in-Part of U.S. application Ser. No. 12/965,480, filed Dec. 10, 2010, which a Continuation of International Application PCT/US2009/046951, filed Jun. 10, 2009. International Application PCT/US2009/046951 claims the benefit of priority of U.S. Provisional Applications: No. 61/060,440, filed Jun. 10, 2008; No. 61/060,445, filed Jun. 10, 2008; No. 61/060,450, filed Jun. 10, 2008; No. 61/100,635, filed Sep. 26, 2008; No. 61/100,652, filed Sep. 26, 2008; No. 61/117,901, filed Nov. 25, 2008; No. 61/122,563, filed Dec. 15, 2008; and No. 61/138,920, filed Dec. 18, 2008: all of which are incorporated by reference in their entireties herein.

This application is a Continuation-in-Part of U.S. application Ser. No. 13/203,713, filed Aug. 26, 2011 which is a 371 National Phase application of PCT/US2009/058632, filed Sep. 28, 2009. International Application PCT/US2009/058632 priority of claims the benefit of priority of U.S. Provisional Application No. 61/100,635, filed Sep. 26, 2008; U.S. Provisional Application No. 61/100,652, filed Sep. 26, 2008; U.S. Provisional Application No. 61/117,901, filed Nov. 25, 2008; U.S. Provisional Application No. 61/122,563, filed Dec. 15, 2008; and U.S. Provisional Application No. 61/138,920, filed Dec. 18, 2008: all of which are incorporated by reference in their entireties herein.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to devices, tools and methods for providing reinforcement of bones. More specifically, the present invention relates to devices, tools and methods for providing reconstruction and reinforcement of bones, including diseased, osteoporotic and/or fractured bones.

2. Description of the Related Art

The number and diversity of sports and work related fractures are being driven by several sociological factors. The diversity of high energy sports has increased and the participation in these sports has followed the general trend of affluence and the resultant amount of time for leisure. High energy sports include skiing, motorcycle riding, snow mobile riding, snowboarding, mountain biking, road biking, kayaking, and all terrain vehicle (ATV) riding. As the general affluence of the economically developed countries has increased the number (or amount) and age of people participating in these activities has increased. Lastly, the acceptance and ubiquitous application of passive restraint systems, airbags, in automobiles has created greater numbers of non-life threatening fractures. In the past, a person that might expire from a serious automobile accident now survives with multiple traumas and resultant fractures.

Bone fractures are a common medical condition both in the young and old segments of the population. However, with an increasingly aging population, osteoporosis has become more of a significant medical concern in part due to the risk of osteoporotic fractures. Osteoporosis and osteoarthritis are among the most common conditions to affect the musculoskeletal system, as well as frequent causes of locomotor pain and disability. Osteoporosis can occur in both human and animal subjects (e.g. horses). Osteoporosis (OP) and osteoarthritis (OA) occur in a substantial portion of the human population over the age of fifty. The National Osteoporosis Foundation estimates that as many as 44 million Americans are affected by osteoporosis and low bone mass, leading to fractures in more than 300,000 people over the age of 65. In 1997 the estimated cost for osteoporosis related fractures was $13 billion. That figure increased to $17 billion in 2002 and is projected to increase to $210-240 billion by 2040. Currently it is expected that one in two women, and one in four men, over the age of 50 will suffer an osteoporosis-related fracture. Osteoporosis is the most important underlying cause of fracture in the elderly. Also, sports and work-related accidents account for a significant number of bone fractures seen in emergency rooms among all age groups.

One current treatment of bone fractures includes surgically resetting the fractured bone. After the surgical procedure, the fractured area of the body (i.e., where the fractured bone is located) is often placed in an external cast for an extended period of time to ensure that the fractured bone heals properly. This can take several months for the bone to heal and for the patient to remove the cast before resuming normal activities.

In some instances, an intramedullary (IM) rod or nail is used to align and stabilize the fracture. In that instance, a metal rod is placed inside a canal of a bone and fixed in place, typically at both ends. See, for example, Fixion™ IM (Nail), www.disc-o-tech.com. Placement of conventional IM rods are typically a “line of sight” and require access collinear with the center line of the IM canal. Invariably, this line of sight access violates, disrupts, and causes damage to important soft tissue structures such as ligaments, tendons, cartilage, fascia, and epidermis. This approach requires incision, access to the canal, and placement of the IM nail. The nail can be subsequently removed or left in place. A conventional IM nail procedure requires a similar, but possibly larger, opening to the space, a long metallic nail being placed across the fracture, and either subsequent removal, and or when the nail is not removed, a long term implant of the IM nail. The outer diameter of the IM nail must be selected for the minimum inside diameter of the space. Therefore, portions of the IM nail may not be in contact with the canal. Further, micro-motion between the bone and the IM nail may cause pain or necrosis of the bone. In still other cases, infection can occur. The IM nail may be removed after the fracture has healed. This requires a subsequent surgery with all of the complications and risks of a later intrusive procedure. In general, rigid IM rods or nails are difficult to insert, can damage the bone and require additional incisions for cross-screws to attach the rods or nails to the bone.

Some IM nails are inflatable. See, for example, Meta-Fix IM Nailing System, www.disc-o-tech.com. Such IM nails require inflating the rod with very high pressures, endangering the surrounding bone. Inflatable nails have many of the same drawbacks as the rigid IM nails described above.

External fixation is another technique employed to repair fractures. In this approach, a rod may traverse the fracture site outside of the epidermis. The rod is attached to the bone with trans-dermal screws. If external fixation is used, the patient will have multiple incisions, screws, and trans-dermal infection paths. Furthermore, the external fixation is cosmetically intrusive, bulky, and prone to painful inadvertent manipulation by environmental conditions such as, for example, bumping into objects and laying on the device.

Other concepts relating to bone repair are disclosed in, for example, U.S. Pat. No. 5,108,404 to Scholten for Surgical Protocol for Fixation of Bone Using Inflatable Device; U.S. Pat. No. 4,453,539 to Raftopoulos et al. for Expandable Intramedullary Nail for the Fixation of Bone Fractures; U.S. Pat. No. 4,854,312 to Raftopolous for Expanding Nail; U.S. Pat. No. 4,932,969 to Frey et al. for Joint Endoprosthesis; U.S. Pat. No. 5,571,189 to Kuslich for Expandable Fabric Implant for Stabilizing the Spinal Motion Segment; U.S. Pat. No. 4,522,200 to Stednitz for Adjustable Rod; U.S. Pat. No. 4,204,531 to Aginsky for Nail with Expanding Mechanism; U.S. Pat. No. 5,480,400 to Berger for Method and Device for Internal Fixation of Bone Fractures; U.S. Pat. No. 5,102,413 to Poddar for Inflatable Bone Fixation Device; U.S. Pat. No. 5,303,718 to Krajicek for Method and Device for the Osteosynthesis of Bones; U.S. Pat. No. 6,358,283 to Hogfors et al. for Implantable Device for Lengthening and Correcting Malpositions of Skeletal Bones; U.S. Pat. No. 6,127,597 to Beyar et al. for Systems for Percutaneous Bone and Spinal Stabilization, Fixation and Repair; U.S. Pat. No. 6,527,775 to Warburton for Interlocking Fixation Device for the Distal Radius; U.S. Patent Publication US2006/0084998 A1 to Levy et al. for Expandable Orthopedic Device; and PCT Publication WO 2005/112804 A1 to Myers Surgical Solutions, LLC et. al. for Fracture Fixation and Site Stabilization System. Other fracture fixation devices, and tools for deploying fracture fixation devices, have been described in: U.S. Patent Appl. Publ. No. 2006/0254950; U.S. Ser. No. 60/867,011 (filed Nov. 22, 2006); U.S. Ser. No. 60/866,976 (filed Nov. 22, 2006); and U.S. Ser. No. 60/866,920 (filed Nov. 22, 2006).

In view of the foregoing, it would be desirable to have a device, system and method for providing effective and minimally invasive bone reinforcement and fracture fixation to treat fractured or diseased bones, while improving the ease of insertion, eliminating cross-screw incisions and minimizing trauma.

SUMMARY

As used herein, the term “aspect” may be used interchangeably with the term “embodiment.” Aspects of the invention relate to embodiments of a bone fixation device and to methods for using such a device for repairing a bone fracture. The bone fixation device may include an elongate body with a longitudinal axis, and/or having a flexible state and a rigid state. The device further may include a plurality of grippers disposed at longitudinally-spaced locations along the elongated body, a rigid hub connected to the elongated body, and an actuator that is operably-connected to the grippers to deploy the grippers from a first shape to an expanded second shape. In various embodiments, the elongate body and the rigid hub may or may not be collinear or parallel.

In one embodiment, a bone fixation device is provided with an elongate body having a longitudinal axis and having a first state in which at least a portion of the body is flexible and a second state in which the body is generally rigid, an actuatable bone engaging mechanism disposed on the elongate body, and an actuator operably connected to the bone engaging mechanism to actuate the bone engaging mechanism from a disengaged configuration to an engaged configuration. In one embodiment, a bone fixation device is provided with an elongate body having a longitudinal axis and having a first state in which at least a portion of the body is flexible and a second state in which the body is generally rigid, an actuatable gripper disposed at a distal location on the elongated body, a hub located on a proximal end of the elongated body, and an actuator operably connected to the gripper to deploy the gripper from a retracted configuration to an expanded configuration.

In one embodiment, a bone fixation device is provided with an elongate body having a longitudinal axis and having a first state in which at least a portion of the body is flexible and a second state in which the body is generally rigid, an actuatable gripper disposed at a location on the elongated body, a hub located on a proximal end of the elongated body, and an actuator operably connected to the gripper to deploy the gripper from a retracted configuration to an expanded configuration.

In one embodiment, a bone fixation device is provided with an elongate body having a longitudinal axis and having a first state in which at least a portion of the body is flexible and a second state in which the body is generally rigid, an actuatable gripper disposed at a distal location on the elongated body, a hub located on a proximal end of the elongated body, and an actuator operably connected to the gripper to deploy the gripper from a retracted configuration to an expanded configuration.

Methods of repairing a fracture of a bone are also disclosed. One such method comprises inserting a bone fixation device into an intramedullary space of the bone to place at least a portion of an elongate body of the fixation device in a flexible state on one side of the fracture and at least a portion of a hub on another side of the fracture, and operating an actuator to deploy at least one gripper of the fixation device to engage an inner surface of the intramedullary space to anchor the fixation device to the bone.

Another such method of repairing a fracture of a clavicle, the clavicle having a lateral segment adjacent to the acromion of a scapula and a medial segment adjacent to the manubrium of a sternum comprises creating an intramedullary channel, such that the channel traverses the fracture of the clavicle and comprises at least one segment that substantially follows a curved anatomical contour of the clavicle; and inserting a bone fixation device into the intramedullary channel and across the fracture of the clavicle, such that at least a portion of an elongate body of the fixation device in a flexible state is placed within the curved segment of the channel.

According to aspects of the present disclosure, similar methods involve repairing a fracture of a metatarsal, metacarpal, sternum, tibia, rib, midshaft radius, ulna, olecranon (elbow), huberus, or distal fibula. Each of these bones have a distal and proximal segment, farthest and closest to the heart, respectively, and on opposite ends of a fracture. The method comprises creating an intramedullary channel, such that the channel traverses the fracture of the bone and comprises at least one segment that substantially follows a curved anatomical contour of the bone; and inserting a bone fixation device into the intramedullary channel and across the fracture of the bone, such that at least a portion of an elongate body of the fixation device in a flexible state is placed within the curved segment of the channel.

One embodiment of the present invention provides a low weight to volume mechanical support for fixation, reinforcement and reconstruction of bone or other regions of the musculo-skeletal system in both humans and animals. The method of delivery of the device is another aspect of the invention. The method of delivery of the device in accordance with the various embodiments of the invention reduces the trauma created during surgery, decreasing the risks associated with infection and thereby decreasing the recuperation time of the patient. The framework may in one embodiment include an expandable and contractible structure to permit re-placement and removal of the reinforcement structure or framework.

In accordance with the various embodiments of the present invention, the mechanical supporting framework or device may be made from a variety of materials such as metal, composite, plastic or amorphous materials, which include, but are not limited to, steel, stainless steel, cobalt chromium plated steel, titanium, nickel titanium alloy (Nitinol), super-elastic alloy, and polymethylmethacrylate (PMMA). The device may also include other polymeric materials that are biocompatible and provide mechanical strength, that include polymeric material with ability to carry and delivery therapeutic agents, that include bioabsorbable properties, as well as composite materials and composite materials of titanium and polyetheretherketone (PEEK), composite materials of polymers and minerals, composite materials of polymers and glass fibers, composite materials of metal, polymer, and minerals.

Within the scope of the present invention, each of the embodiments of types of devices may further be coated with proteins from synthetic or animal source, or include collagen coated structures, and radioactive or brachytherapy materials. Furthermore, the construction of the supporting framework or device may include radio-opaque markers or components that assist in their location during and after placement in the bone or other region of the musculo-skeletal systems.

Further, the reinforcement device may, in one embodiment, be osteo incorporating, such that the reinforcement device may be integrated into the bone.

In still another embodiment of the invention, a method of repairing a bone fracture is disclosed that comprises: accessing a fracture along a length of a bone through a bony protuberance at an access point at an end of a bone; advancing a bone fixation device into a space through the access point at the end of the bone; bending a portion of the bone fixation device along its length to traverse the fracture; and locking the bone fixation device into place within the space of the bone. The method can also include the step of advancing an obturator through the bony protuberance and across the fracture prior to advancing the bone fixation device into the space. In yet another embodiment of the method, the step of anchoring the bone fixation device within the space can be included.

In another embodiment of the invention, a method of repairing bone is disclosed whereby the area of the affected bone is remediated by advancing the device through an opening in the middle of the bone, below the metaphysis or at a point away from a joint or bony protuberance.

An aspect of the invention discloses a removable bone fixation device that uses a single port of insertion and has a single-end of remote actuation wherein a bone fixation device stabilizes bone after it has traversed the fracture. The bone fixation device is adapted to provide a single end in one area or location where the device initiates interaction with bone. The device can be deployed such that the device interacts with bone. Single portal insertion and single-end remote actuation enables the surgeon to insert and deploy the device, deactivate and remove the device, reduce bone fractures, displace or compress the bone, and lock the device in place. In addition, the single-end actuation enables the device to grip bone, compresses the rigidizable flexible body, permits axial, torsional and angular adjustments to its position during surgery, and releases the device from the bone during its removal procedure. A removable extractor can be provided in some embodiments of the device to enable the device to be placed and extracted by deployment and remote actuation from a single end. The device of the invention can be adapted and configured to provide at least one rigidizable flexible body or sleeve. Further the body can be configured to be flexible in all angles and directions. The flexibility provided is in selective planes and angles in the Cartesian, polar, or cylindrical coordinate systems. Further, in some embodiments, the body is configured to have a remote actuation at a single end. Additionally, the body can be configured to have apertures, windings, etc. The device may be configured to function with non-flexible bodies for use in bones that have a substantially straight segment or curved segments with a constant radius of curvature. Another aspect of the invention includes a bone fixation device in that has mechanical geometry that interacts with bone by a change in the size of at least one dimension of a Cartesian, polar, or spherical coordinate system. Further, in some embodiments, bioabsorbable materials can be used in conjunction with the devices, for example by providing specific subcomponents of the device configured from bioabsorbable materials. A sleeve can be provided in some embodiments where the sleeve is removable, has deployment, remote actuation, and a single end. Where a sleeve is employed, the sleeve can be adapted to provide a deployable interdigitation process or to provide an aperture along its length through which the deployable interdigitation process is adapted to engage bone. In some embodiments, the deployable interdigitation process is further adapted to engage bone when actuated by the sleeve. In some embodiments, the bone fixation device further comprises a cantilever adapted to retain the deployable bone fixation device within the space. The sleeve can further be adapted to be expanded and collapsed within the space by a user. One end of the device can be configured to provide a blunt obturator surface adapted to advance into the bone. A guiding tip may also be provided that facilitates guiding the device through the bone. The device may be hollow and accept a guide wire. The guiding tip may facilitate placement of the device thereby providing a means to remove bone in its path (a helical end, a cutting end, or ablative end). The guiding tip may allow capture, interaction, or insertion into or around a tube on its internal or external surface. Further, the deployable bone fixation device can be adapted to receive external stimulation to provide therapy to the bone. The device can further be adapted to provide an integral stimulator which provides therapy to the bone. In still other embodiments, the device can be adapted to receive deliver therapeutic stimulation to the bone.

The devices disclosed herein may be employed in various regions of the body, including: spinal, cranial, thoracic, lower extremities and upper extremities. Additionally, the devices are suitable for a variety of breaks including, epiphyseal, metaphyseal, diaphyseal cortical bone, cancellous bone, and soft tissue such as ligament attachment and cartilage attachment.

The fracture fixation devices of various embodiments of the invention are adapted to be inserted through an opening of a fractured bone, such as the radius (e.g., through a bony protuberance on a distal or proximal end or through the midshaft) into an intramedullary canal of the bone. The device can be inserted in one embodiment in a line of sight manner collinear or nearly collinear, or parallel to the central axis of the intramedullary canal. In another embodiment, the device can be inserted at an angle, radius, or tangency to the axis of the intramedullary canal. In another embodiment, the device can be inserted in a manner irrespective of the central axis of the intramedullary canal. In some embodiments, the fixation device has two main components, one configured component for being disposed on the side of the fracture closest to the opening and one component configured for being disposed on the other side of the fracture from the opening so that the fixation device traverses the fracture.

The device components cooperate to align, fix and/or reduce the fracture so as to promote healing. The device may be removed from the bone after insertion (e.g., after the fracture has healed or for other reasons), or it may be left in the bone for an extended period of time or permanently.

In some embodiments, the fracture fixation device has one or more actuatable bone engaging mechanisms such as anchors or grippers on its proximal and/or distal ends. These bone engaging mechanisms may be used to hold the fixation device to the bone while the bone heals. In another embodiment, the fracture fixation device has a plurality of actuatable bone engaging mechanisms such as grippers or anchors along its length. In another embodiment, the fracture fixation device has grippers or anchoring devices that interdigitate into the bone at an angle greater than zero degrees and less than 180 degrees to secure the bone segments of the fracture. In another embodiment the fracture fixation device has grippers or anchoring features that when activated from a state that facilitates insertion to a state that captures, aligns, and fixes the fracture, deploy in a geometry so that the resultant fixed bone is analogous or nearly identical, or identical to the geometry of the bone prior to the fracture. In one embodiment of the device, the flexible body allows insertion through tortuous paths within bone or created within bone. Upon activation from the state of insertion to the state of fixation, this device deforms so as to grip the bone upon multiple surfaces of the now collapsed, rigid, flexible body. In this collapsed state the device may be deform in such a way to re-achieve anatomical alignment of the bone. The device as described above can be fabricated so that it can have any cross sectional shape. Examples of cross sectional shapes include round, oval, square, rectangular, n-sided, where n is an integer from 1 to infinity, star shaped, spoke shaped.

In some embodiments, to aid in insertion of the device into the intramedullary canal, the main component of the fracture fixation device has a substantially flexible state. Thereby, the device, prior to activation, may not have a rigid section. Once in place, deployment of the device also causes the components to change from the flexible state to a rigid state to aid in proper fixation of the fracture. In some embodiments, at least one of the components may be semi-flexible. Placement of the device may be aided by a detachable rigid member such as a guide or outrigger. Placement of the device may be aided by removable rigid member such as a tube or guide wire. In some embodiments, at least one component may provide a bone screw attachment site for the fixation device. In some embodiments, at least one of the components of the device may allow a screw or compressive member to be attached along its axis to provide linear compression of one side of the fractured bone towards the other (e.g. compression of the distal segment towards the proximal segment or visa versa). In some embodiments, at least one of the components of the device may accept a screw at an acute angle, and angle less than 30 degrees from the axis of the device that would allow compression of one side of the fractured bone towards the other. In some embodiments, at least one of the components of the device may accept an alternately removable eyelet to accommodate a compressive device so as to compress one side of the fractured bone towards the other side.

In some embodiments, to aid in insertion into the intramedullary canal, at least one component of the fracture fixation device has a substantially flexible state and a substantially rigid state. Once in place, deployment of the device also causes the components to change from the flexible state to a rigid state to aid in proper fixation of the fracture. In some embodiments, at least one of the components may be substantially rigid or semi-flexible. In some embodiments, at least one component may provide a bone screw attachment site for the fixation device.

Embodiments of the invention also provide deployment tools with a tool guide for precise alignment of one or more bone screws with the fracture fixation device. These embodiments also provide bone screw orientation flexibility so that the clinician can select an orientation for the bone screw(s) that will engage the fixation device as well as any desired bone fragments or other bone or tissue locations.

These and other features and advantages of the present invention will be understood upon consideration of the following detailed description of the invention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

FIG. 1 depicts the skeletal system of the pectoral girdles.

FIG. 2 show the superior surface of a left clavicle.

FIG. 3 is a side view of an embodiment of a bone repair device constructed according to aspects of the invention.

FIG. 4 shows the device ofFIG. 3 in a deployed state.

FIG. 5 is an exploded view showing the components of the device shown inFIG. 3.

FIGS. 6A and 6B are perspective views showing a coupling member.

FIGS. 7A and 7B are perspective views showing a distal gripper.

FIGS. 8A and 8B are perspective views showing a proximal gripper.

FIG. 9 is a cross-section view of the device ofFIG. 3 in a retracted state.

FIG. 10 is a cross-section view of the device ofFIG. 3 in a deployed state.

FIG. 11 is a superior view showing the device ofFIG. 3 implanted in a right clavicle.

FIG. 12 is a posterior view showing the device ofFIG. 3 implanted in a right clavicle.

FIG. 13 is a side view of an alternative embodiment.

FIG. 14 is a top view of an alternative embodiment.

FIG. 15 is a perspective view of an alternative embodiment.

FIG. 16 is a side view of an alternative embodiment.

FIGS. 17 and 18 are a perspective view and a cross-section view, respectively, of an alternative embodiment.

FIGS. 19 and 20 are a side view and a cross-section view, respectively, of an alternative embodiment.

FIGS. 21-23 are a perspective view, a cross-section view, and an exploded view respectively, of an alternative embodiment.

FIG. 24 is a side view of an embodiment of a depth gauge.

FIG. 25 is a side view of a first embodiment of a protection tool.

FIGS. 26 and 27 are a side view and an exploded view, respectively, of a second embodiment of a protection tool.

FIG. 28 is a perspective view of an embodiment of a bone fixation device implanted in a bone according to the invention.

FIG. 29 is another perspective view of the implanted device ofFIG. 28.

FIG. 30 is a longitudinal cross-section view of the bone fixation device ofFIG. 28 in a non-deployed state.

FIG. 31 is a plan view of a combination deployment tool that may be used with the bone fixation device ofFIG. 28.

FIG. 32 is a cross-section view of the tool and device shown inFIG. 31.

FIG. 33 is a perspective view of the tool and device shown inFIG. 31.

FIG. 34A is a cross-section view of the implanted device ofFIG. 28.

FIG. 34B is a plan view of an alternative combination deployment tool that may be used with the bone fixation device ofFIG. 28.

FIG. 35 is a perspective view of an alternative embodiment of the implanted device ofFIG. 28.

FIG. 36 is a perspective view of another alternative embodiment of the implanted device ofFIG. 28.

FIG. 37A is a perspective view of another embodiment of a bone fixation device shown deployed in a fractured clavicle.

FIG. 37B is perspective view of the device shown inFIG. 37A shown in a deployed state.

FIG. 37C is a side elevation view of the device shown inFIG. 37A shown in a retracted or undeployed state.

FIG. 37D is a side elevation view of the device shown inFIG. 37A shown in a deployed state.

FIG. 37E is a cross-sectional view of the device shown inFIG. 37A shown in a retracted or undeployed state.

FIG. 37F is a cross-sectional view of the device shown inFIG. 37A shown in a deployed state.

FIG. 37G is a perspective view of a gripper of the device shown inFIG. 37A shown in a retracted or undeployed state.

FIG. 37H is a side elevation view of a gripper and actuator of the device shown inFIG. 37A shown in a retracted or undeployed state.

FIG. 37I is a perspective view of a gripper and actuator of the device shown inFIG. 37A shown in a deployed state.

FIG. 38A is perspective view of another embodiment of a bone fixation device shown in a retracted or undeployed state.

FIG. 38B is perspective view of the device shown inFIG. 38A shown in a deployed state.

FIG. 38C is a cross-sectional view of the device shown inFIG. 38A shown in a retracted or undeployed state.

FIG. 38D is a cross-sectional view of the device shown inFIG. 38A shown in a deployed state.

FIGS. 39A-39F show various views of an exemplary embodiment of a bone fixation device hub.

FIGS. 39G-39I show various views of an exemplary embodiment of a bone fixation device implanted in a bone.

FIGS. 40A-40E show various views of another exemplary embodiment of a bone fixation device hub.

FIGS. 41A-41F show various views of another exemplary embodiment of a bone fixation device hub.

FIGS. 42A-42D show various views of another exemplary embodiment of a bone fixation device hub.

FIGS. 43A-43E show various views of another exemplary embodiment of a bone fixation device hub.

FIGS. 44A-44C show various views of another exemplary embodiment of a bone fixation device hub.

FIGS. 45A-45B show various views of another exemplary embodiment of a bone fixation device hub.

FIGS. 46A-46B show various views of another exemplary embodiment of a bone fixation device hub.

FIGS. 47A-47B show various views of another exemplary embodiment of a bone fixation device hub.

FIG. 48A is a perspective view showing another alternative gripper design in a retracted or undeployed state.

FIG. 48B is a side elevational view showing the gripper ofFIG. 48A in a retracted or undeployed state.

FIG. 48C is a perspective view showing the gripper ofFIG. 48A in a deployed state.

FIG. 48D is an end view showing the gripper ofFIG. 48A in a deployed state.

FIG. 49A is a perspective view showing another alternative gripper design in a retracted or undeployed state.

FIG. 49B is a side elevational view showing the gripper ofFIG. 49A in a retracted or undeployed state.

FIG. 50 A is a perspective view showing another alternative gripper design in a retracted or undeployed state.

FIG. 50B is a side elevational view showing the gripper ofFIG. 50 A in a retracted or undeployed state.

FIG. 51A is a perspective view showing another alternative gripper design in a retracted or undeployed state.

FIG. 51B is a side elevational view showing the gripper ofFIG. 51A in a retracted or undeployed state.

FIG. 52A is a perspective view showing another alternative gripper design in a retracted or undeployed state.

FIG. 52B is a side elevational view showing the gripper ofFIG. 52A in a retracted or undeployed state.

FIG. 53 A is a perspective view showing another alternative gripper design in a retracted or undeployed state.

FIG. 53 B is a side elevational view showing the gripper ofFIG. 53 A in a retracted or undeployed state.

FIG. 54A is a perspective view showing another bone fixation device in a retracted or undeployed state.

FIG. 54B is a top plan view showing the device ofFIG. 54 A in a retracted or undeployed state.

FIG. 54C is a side elevational view showing the device ofFIG. 54A in a retracted or undeployed state.

FIG. 54D is a perspective view showing the device ofFIG. 54A in a deployed state.

FIG. 54E is a top plan view showing the device ofFIG. 54A in a deployed state.

FIG. 54F is a side elevational view showing the device ofFIG. 54A in a deployed state.

FIG. 55A is an enlarged perspective view showing just the distal gripper of the device ofFIG. 54A in a retracted or undeployed state.

FIG. 55B is a side elevational view showing the gripper ofFIG. 55A in a retracted or undeployed state.

FIG. 55C is a top plan view showing the gripper ofFIG. 55A in a retracted or undeployed state.

FIG. 55D is a perspective view showing the gripper ofFIG. 55A in a deployed state.

FIG. 55E is a side elevational view showing the gripper ofFIG. 55A in a deployed state.

FIG. 55 F is a top plan view showing the gripper ofFIG. 55A in a deployed state.

FIG. 55G is an exploded perspective view showing the gripper ofFIG. 55A.

FIGS. 56-58 are various views showing another embodiment of a bone fixation device.

FIGS. 59-65 are schematic cross-sectional side and oblique views of an embodiment of a bone fixation device with a compression screw.

FIGS. 66-67 are views showing another embodiment of a bone fixation device.

FIG. 68 is a perspective view showing the device ofFIGS. 66-67 coupled with a screw hole forming guide tool.

FIGS. 69-70 are various views showing another embodiment of a bone fixation device.

FIGS. 71-74 are various views showing another embodiment of a bone fixation device.

FIGS. 75-78 are various views showing another embodiment of a bone fixation device.

FIG. 79 is a perspective view showing another embodiment of a flexible-to-rigid body portion of a bone fixation device.

FIG. 80 is a plan view showing part of the cut pattern of the body portion ofFIG. 79 laid flat.

FIG. 81 is a perspective view showing another embodiment of a flexible-to-rigid body portion of a bone fixation device.

FIG. 82A is a plan view showing part of the cut pattern of the body portion ofFIG. 81 laid flat.

FIG. 82B is a plan view showing part of a cut pattern laid flat, similar to the one shown inFIGS. 81 and 82 A.

FIG. 83 is a perspective view showing another embodiment of a flexible-to-rigid body portion of a bone fixation device.

FIG. 84 is a plan view showing part of the cut pattern of the body portion ofFIG. 83 laid flat.

FIG. 85 is a perspective view showing another embodiment of a flexible-to-rigid body portion of a bone fixation device.

FIG. 86 is a plan view showing part of the cut pattern of the body portion ofFIG. 85 laid flat.

FIG. 87 is a perspective view showing another embodiment of a flexible-to-rigid body portion of a bone fixation device.

FIG. 88 is a plan view showing the cut pattern of the body portion ofFIG. 87 laid flat.

FIG. 89 is a perspective view of an exemplary rotary driver tool constructed according to aspects of the invention.

FIG. 90 is a proximally-looking exploded view showing the driver tool ofFIG. 89.

FIG. 91 is a distally-looking exploded view showing the driver tool ofFIG. 89.

FIG. 92 is a longitudinal cross-sectional view of the driver tool ofFIG. 89.

FIG. 93 is a perspective view of the driver tool ofFIG. 89 with the knob, cap and retaining ring removed to more clearly show the other components of the tool.

FIG. 94 is an exploded view showing a variation of the combination tool ofFIG. 31.

FIG. 95 is a perspective view showing a variation of the bone repair device ofFIG. 28.

FIG. 96A is a perspective view showing an alternative bone repair device.

FIG. 96B is a cross-section view showing the device ofFIG. 96A.

FIG. 96C is an exploded view showing the device ofFIG. 96A.

FIG. 97 is a side view of one embodiment of a shape-conforming flexible-to-rigid body portion.

FIG. 98A is a side view of another embodiment of a shape-conforming flexible-to-rigid body portion.

FIG. 98B is a perspective view of yet another embodiment of a shape-conforming flexible-to-rigid body portion.

FIG. 99A is a perspective view showing another body portion embodiment having interlocking features.

FIG. 99B is a longitudinal cross-sectional view of the body portion shown inFIG. 99A.

FIG. 99C is a perspective view showing another body portion embodiment having interlocking features.

FIG. 99D is a longitudinal cross-sectional view of the body portion shown inFIG. 99C.

FIG. 99E is a perspective view showing another body portion embodiment having interlocking features.

FIG. 99F is a longitudinal cross-sectional view of the body portion shown inFIG. 99E.

FIG. 99G is a perspective view showing another body portion embodiment having interlocking features.

FIG. 99H is a longitudinal cross-sectional view of the body portion shown inFIG. 99G.

FIG. 99I is a perspective view showing another body portion embodiment having interlocking features.

FIG. 99J is a longitudinal cross-sectional view of the body portion shown inFIG. 99I.

FIG. 100A is a cross-sectional view showing the proximal end of a device employing the body portion ofFIG. 97, the device being shown in a flexible state.

FIG. 100B is a cross-sectional view showing the proximal end of a device employing the body portion ofFIG. 97, the device being shown in a shape-conforming state.

FIG. 101A is a side view showing a device employing two body portions ofFIG. 97, the device being shown in a flexible state.

FIG. 101B is a cross-sectional view showing a device employing two body portions ofFIG. 97, the device being shown in a flexible state.

FIG. 101C is a cross-sectional view showing a device employing two body portions ofFIG. 97, the device being shown in a shape-conforming state.

FIG. 101D is a partially exploded perspective view showing a device employing two body portions ofFIG. 98B, the device being shown in a flexible state.

FIG. 101E is a cross-sectional view showing a device employing two body portions ofFIG. 98B, the device being shown in a flexible state.

FIG. 102 is plan view depicting a device similar to that ofFIGS. 101A-101C, the device being shown deployed in a clavicle.

FIG. 103 is a perspective view showing a device similar to that ofFIGS. 101A-101C, the device being introduced into the intramedullary space of a clavicle.

FIG. 104 is a side view showing an alternative embodiment device in a deployed, shape-conforming state and having alternative anchors.

FIG. 105 is a side view showing another alternative embodiment device in a deployed, shape-conforming state.

FIG. 106 is a perspective view showing another exemplary embodiment of a bone fixation device attached to tools that may be used for its insertion, deployment, and removal.

FIG. 107 is an exploded view showing the components of the bone fixation device and insertion/removal tool ofFIG. 106.

FIG. 108 is an enlarged perspective view showing the bone fixation device ofFIG. 106.

FIG. 109 is an enlarged, cut-away perspective view showing internal components of the device ofFIG. 106.

FIGS. 110A-110D are enlarged perspective views showing details of various components of the device ofFIG. 106.

FIG. 110E is a plan view showing an exemplary interlocking pattern that may be used in the device ofFIG. 106.

FIG. 111 is a longitudinal cross-section view showing the device and a portion of the tools ofFIG. 106.

FIG. 112 is a perspective view showing the device ofFIG. 106 in a deployed state.

FIG. 113 is a cut-away perspective view showing the device and tools ofFIG. 106 with a guide wire inserted therethrough.

FIG. 114 is an enlarged cross-section view showing the device, tools and guide wire ofFIG. 113.

FIGS. 115 and 116 are plan views showing exemplary patterns that may be used in the flexible-to-rigid body portions of bone fixation devices.

FIGS. 117A-117H are views showing an overlapping flexible-to-rigid body portion, whereFIG. 117A is a plan view,FIG. 117B is an enlarged cross-sectional side view of the body portion in an expanded, flexible state,FIG. 117C is an enlarged cross-sectional side view of the body portion in a compressed, rigid state, andFIGS. 117D-117H are enlarged plan views showing various tip configurations.

FIGS. 118A-118C are views showing an exemplary flexible-to-rigid body portion having an oval cross-section, whereFIG. 118A is a side view showing the device in a flexible state,FIG. 118B is a side view showing the device in a rigid state, andFIG. 118C is a cross-section taken alongline118C-118C inFIG. 118A.

FIGS. 119A-119C are views showing an exemplary flexible-to-rigid body portion having a square cross-section, whereFIG. 119A is a side view showing the device in a flexible state,FIG. 119B is a side view showing the device in a rigid state, andFIG. 119C is a cross-section taken alongline119C-119C inFIG. 119A.

FIGS. 120A-120E show an alternative embodiment of a bone fixation device.

FIGS. 121A-121E show an alternative embodiment of a bone fixation device.

FIGS. 122A-122B show an alternative embodiment of a bone fixation device.

FIG. 123 is a schematic flattened side view of a segmented flexible-to-rigid body portion of a bone fracture implant according to an embodiment of the present invention.

FIG. 124 is a schematic partial side view of the segmented implant according toFIG. 123.

FIG. 125 is a schematic partial other side view of the segmented implant according toFIG. 123.

FIG. 126 is a schematic partial cross-sectional side view of the segmented implant according toFIG. 125.

FIG. 127 is a schematic flattened side view of a segmented flexible-to-rigid body portion of a bone fracture implant according to an embodiment of the present invention.

FIG. 128 is a schematic side view of the segmented implant according toFIG. 127.

FIG. 129 is a schematic other side view of the segmented implant according toFIG. 127.

FIG. 130 is a schematic side view of the segmented implant with details on the segments removed according toFIG. 127.

FIG. 131 is a schematic cross-sectional view of a cannulated fixation implant according toFIG. 130.

FIG. 132 is a schematic side view of a segmented flexible-to-rigid body portion of a bone fracture implant in a straightened configuration according to an embodiment of the present invention.

FIG. 133 is a schematic side view of the segmented implant in a curved configuration according toFIG. 132.

FIG. 134 is a schematic side view of a segmented flexible-to-rigid body portion of a bone fracture implant in a curved configuration according to an embodiment of the present invention.

FIG. 135 is a schematic side view of a segmented flexible-to-rigid body portion of a bone fracture implant in a curved configuration according to an embodiment of the present invention.

FIG. 136 is a schematic side view of a segmented flexible-to-rigid body portion of a bone fracture implant in a curved configuration according to an embodiment of the present invention.

FIG. 137 is a chart illustrating results from an experimental setup with various embodiments of implants of the present invention.

FIG. 138 is a chart illustrating results from an experimental setup with various embodiments of implants of the present invention.

FIG. 139 is a chart illustrating results from an experimental setup with various embodiments of implants of the present invention.

FIG. 140 is a chart illustrating results from an experimental setup with various embodiments of implants of the present invention.

FIG. 141 is a schematic side isometric view of a flexible-to-rigid body sleeve of a bone fracture implant according to an embodiment of the present invention.

FIG. 142 is a schematic side view of a flexible-to-rigid body sleeve and a bone fracture implant according to an embodiment of the present invention.

FIG. 143 is a schematic side view of the flexible-to-rigid body sleeve attached to the segmented flexible-to-rigid body portion of the bone fracture implant ofFIG. 142.

FIG. 144 is a schematic side view of a segmented flexible-to-rigid body portion of a bone fracture implant according to an embodiment of the present invention.

FIG. 145 is a schematic side view of the flexible-to-rigid body sleeve ofFIG. 144 on the segmented flexible-to-rigid body portion ofFIG. 144.

FIG. 146 is a cross-sectional side view of the flexible-to-rigid body sleeve ofFIG. 144 on the segmented flexible-to-rigid body portion ofFIG. 144.

DETAILED DESCRIPTION

By way of background and to provide context for the invention, it may be useful to understand that bone is often described as a specialized connective tissue that serves three major functions anatomically. First, bone provides a mechanical function by providing structure and muscular attachment for movement. Second, bone provides a metabolic function by providing a reserve for calcium and phosphate. Finally, bone provides a protective function by enclosing bone marrow and vital organs. Bones can be categorized as long bones (e.g. radius, femur, tibia and humerus) and flat bones (e.g. skull, scapula and mandible). Each bone type has a different embryological template. Further each bone type contains cortical and trabecular bone in varying proportions. The devices of this invention can be adapted for use in any of the bones of the body as will be appreciated by those skilled in the art.

Cortical bone (compact) forms the shaft, or diaphysis, of long bones and the outer shell of flat bones. The cortical bone provides the main mechanical and protective function. The trabecular bone (cancellous) is found at the end of the long bones, or the epiphysis, and inside the cortex of flat bones. The trabecular bone consists of a network of interconnecting trabecular plates and rods and is the major site of bone remodeling and resorption for mineral homeostasis. During development, the zone of growth between the epiphysis and diaphysis is the metaphysis. Finally, woven bone, which lacks the organized structure of cortical or cancellous bone, is the first bone laid down during fracture repair. Once a bone is fractured, the bone segments are positioned in proximity to each other in a manner that enables woven bone to be laid down on the surface of the fracture. This description of anatomy and physiology is provided in order to facilitate an understanding of the invention. Persons of skill in the art will also appreciate that the scope and nature of the invention is not limited by the anatomy discussion provided. Further, it will be appreciated there can be variations in anatomical characteristics of an individual patient, as a result of a variety of factors, which are not described herein. Further, it will be appreciated there can be variations in anatomical characteristics between bones which are not described herein.

While the inventive devices, tools and methods described herein may be adapted for use with many regions of the musculo-skeletal system in both humans and animals, they are particularly well suited for addressing fractures in the human clavicle, also known as the collar bone. Clavicle fractures involve approximately 5% of all fractures seen in hospital emergency admissions. The clavicle is most commonly fractured between the proximal ⅔ and distal ⅓ of its length. Fractures often occur when a patient falls onto an outstretched upper extremity, falls onto a shoulder, or receives direct clavicular trauma.

FIG. 1 shows the location of theleft clavicle10 andright clavicle12 in the human anatomy. The clavicle is classified as a membranous bone that makes up part of thepectoral girdles14. The clavicle receives its name from the Latin claviculam, meaning “little key”, because the bone rotates along its axis like a key when the shoulder is abducted. This movement is palpable with the opposite hand. The clavicle is a doubly curved short bone that connects the arm (upper limb) to the body (trunk), located directly above thefirst rib16. It acts as a shunt to keep thescapula18 in position so the arm can hang freely. At itsmedial end20, theclavicle10,12 articulates with the manubrium of the sternum22 (breast-bone) at the sternoclavicular joint. At itslateral end24, theclavicle10,12 articulates with theacromion26 of the scapula (shoulder blade) at the acromioclavicular joint. As mentioned, the clavicle is a double curved bone, comprising a lateral segment having a lateral curve and a medial segment having a medical curve. It has been found by Jonas Andermahr et al. in “Anatomy of the clavicle and the Intramedullary Nailing of Midclavicular Fractures” (Clinical Anatomy 20 (2007): 48-56), that the medial curve radius is about 7.1.+−.1.3 cm overall (N=196) with women (N=106) having a slightly smaller curvature of 7.0.+−.1.2 cm and men (N=90) having a slightly larger curvature of 7.3.+−.1.3 cm. The lateral curve radius is about 3.9.+−.1.4 cm overall (N=196) with women (N=106) having a slightly larger curvature of 4.2.+−.1.6 cm and men (N=90) having a slightly smaller curvature of 3.6.+−.1.1 cm.

FIG. 2 is an enlarged view of the superior surface of theleft clavicle10. As can be seen, theclavicle10 has a rounded medial end (sternal extremity)20 and a flattened lateral end (acromial extremity)24. From the roughly pyramidalsternal end20,clavicle10 curves laterally and posteriorly for roughly half its length. It then forms a smooth posterior curve to articulate with a process of the scapula (acromion), as described above. The flat,acromial end24 of theclavicle10 is broader than thesternal end20. Theacromial end24 has a rough inferior surface that bears prominent lines and tubercles. These surface features are attachment sites for muscles and ligaments of the shoulder. The clavicle is made up of spongy (cancellous) bone with a shell of compact bone. It is a dermal bone derived from elements originally attached to the skull. An exemplarymid-shaft fracture site28 is depicted inFIG. 2.

FIGS. 3 and 4 show an exemplary embodiment of a fracture fixation device according to aspects of the invention. As will be later described,device100 may be implanted in a longitudinal intramedullary cavity ofclavicle10 shown inFIG. 2, or other bones, to approximate and/orsecure fracture28.FIG. 3 showsdevice100 in a retracted state for insertion into or removal from a bone, whileFIG. 4 shows the device in an expanded state as when it is anchored within a bone.

Bone repair device100 has a proximal end102 (nearest the surgeon) and a distal end104 (further from surgeon) and positioned within the bone space of a patient according to the invention. The proximal end and distal end, as used in this context, refers to the position of an end of the device relative to the remainder of the device or the opposing end as it appears in the drawing. The proximal end can be used to refer to the end manipulated by the user or physician. The distal end can be used to refer to the end of the device that is inserted and advanced within the bone and is furthest away from the physician. As will be appreciated by those skilled in the art, the use of proximal and distal could change in another context, e.g. the anatomical context in which proximal and distal use the patient as reference. As described in most instances herein, the device will be implanted into a bone, such as a clavicle, such that the proximal end will be implanted in the lateral segment of the clavicle bone, and the distal end will be implanted in the medial segment of the clavicle bone.

When implanted within a patient, the device can be held in place with suitable fasteners such as wire, screws, nails, bolts, nuts and/or washers. Thedevice100 may be used for fixation of fractures of the proximal or distal end of long bones such as intracapsular, intertrochanteric, intercervical, supracondular, or condular fractures of the femur; for fusion of a joint; or for surgical procedures that involve cutting a bone. Thedevices100 may be implanted or attached through the skin so that a pulling force (traction may be applied to the skeletal system).

In the embodiment shown inFIGS. 3,4, and15, the design of therepair device100 depicted is adapted to provide two bone engaging mechanisms orgrippers108,109, each adapted to engage target bone of a patient from the inside of the bone. As configured for this anatomical application, the device is designed to facilitate bone healing when placed in the intramedullary space within a post fractured bone. Thisdevice100 has agripper108 positioned distally, and anothergripper109 positioned proximally. Both grippers are deployed radially outward against the wall of the intramedullary cavity. On entry into the cavity,grippers108,109 are flat and retracted as shown inFIG. 3. Upon deployment,grippers108,109 pivot radially outward, as shown inFIG. 4, and grip the diaphyseal bone in this embodiment from the inside of the bone. One ormore screws110, shown inFIG. 11, placed through apertures through thehub112 lock thedevice100 to the metaphyseal bone. Hence, the proximal end and or metaphysis and the distal end and or diaphysis are joined. The union between the proximal and distal ends may be achieved by thegrippers108 and109 alone or in concert withscrews110 placed throughhub112.Hub112 may be either at the distal or proximal end of the bone, in this case clavicle. Ahub112 may be at both ends of the device, there by allowing screws to be placed in the distal and proximal ends. A flexible-to-rigid body portion114 may also be provided, and in this embodiment is positioned betweengrippers108 and109. The flexible-to-rigid body portion may be placed proximal or distal to both grippers,108 and109. It may be provided withcut116 that is specific for the purpose and location of the device, as will be described in more detail below.

FIG. 5 shows an exploded view ofdevice100. In this embodiment, device100 (starting at the proximal end and moving towards the distal end) is formed from aproximal body member510,drive member128,keeper ring512,proximal gripper109,bushing514,coupling member516,distal body member518,distal gripper108,actuator126, andtip cover134. During assembly ofdevice100,proximal gripper109 is rotatably received over the reduced diameter portion ofdrive member128 until it abuts against the larger diameter proximal portion ofdrive member128.Keeper ring512 is then slid over the reduced diameter portion ofdrive member128 to the position shown and is welded, pinned, press fit, swaged, adhered and/or otherwise secured in place such that it allowsgripper128 to rotate with respect to drivemember128 but not move axially relative to it.Bushing514 is similarly slid over the reduced diameter portion ofdrive member128 and secured in a position more distal thankeeper ring512. This drive member/gripper assembly is then placed within the axial bore ofproximal body member516.

Each end ofcoupling member516 has a stepped portion of smaller outer diameter than the middle ofcoupling member516. During assembly, the longer, proximal end ofcoupling member516 is received within the distal end of proximal body member510 (after the drive member/gripper assembly is inserted, as described above). The shorter, distal end ofcoupling member516 is received within the proximal end ofdistal body member518. The proximal anddistal body members510,518 are secured tocoupling member516, such as by welding or other suitable means. When assembled,proximal body member510,coupling member516, anddistal body member518 form a smooth tube having a generally constant outer diameter, as shown inFIG. 3.

Distal gripper108 is configured to fit within the distal end ofdistal body member518. The proximal end ofactuator126 may be passed through the center ofdistal gripper108,distal body member518, andcoupling member516 until it reachesdrive member128, which is rotatably housed withinproximal body member510. The distal end ofdrive member128 includes an internally threaded bore for receiving the externally threaded proximal end ofactuator126. Asdrive member128 is rotated with respect toactuator126,actuator126 moves proximally and/or drivemember128 moves distally. Mating features ofactuator126 andcoupling member516, as will be later described, allowactuator126 to move axially but prevent it from rotating.

The assembly ofdevice100 may be completed by attachinghemispherical tip cover134 to the distal end ofdistal body member518, such as by welding or other suitable process.Tip cover134 may be configured to act as a blunt obturator. This arrangement facilitates penetration of bone bydevice100 while keeping the tip ofdevice100 from digging into bone during an insertion procedure. Alternatively, as shown inFIG. 17, the tip may include a screw or threaded tip or, as shown inFIG. 19, the tip may have a conical shape. The tip may have various geometrical configurations that adapt to enabling tools such as guide wires and guide tubes. The tip may be actively coupled to an electrical or mechanical source that removes or ablates bone to facilitate insertion. Variations or alternatives to the exemplary assembly procedure described above will be apparent to those skilled in the art.

FIGS. 6A and 6B show detailed features ofcoupling member516. T-shapedslots610,610 are formed on opposite sides of the proximal end ofcoupling member516. This leaves two T-shapedappendages612,612 which extend in a proximal direction from couplingmember516 when it is assembled indevice100. The outer edges of each T-shapedappendage612 include a ramped surface614,614, the purpose of which will be later described. The inner end of each T-shapedappendage612 is connected to the main body ofcoupling member516 by a necked downportion616,616. The necked downportions616,616 are configured and arranged to bend, allowing T-shapedappendages612,612 to pivot axially inward, as will be later described.

The distal end ofcoupling member516 is provided with an oblong axial slot618. The parallel sides of slot618 mate with the flattened portion520 of actuator126 (shown inFIG. 5) to allowactuator126 to move axially but prevent it from rotating.

FIGS. 7A and 7B show detailed features ofdistal gripper108.Gripper108 includes two pairs of opposingbendable members118. Eachbendable member118 has a thinnedportion120 that connects it to acommon collar710. Thinnedportions120 permit bending as the opposite distal ends122 ofmembers118 are urged radially outward, such thatmembers118 may pivot about thinnedportions120. When radially extended, distal ends122 ofbendable members118 contact the inside of the bone to anchor the distal portion ofdevice100 to the bone, as will be later described. As shown, eachdistal end122 includes a rampedsurface712 to assist in radial deployment, and anotch714 to assist in engaging the inner surface of the bone. In other embodiments, thenotch714 may be replaced with a point, radii, or rectangular geometry. In some embodiments rampedsurface712 is omitted. In other embodiments, it has an angle selected between 0 and 90 degrees. In other embodiments, this surface may have multiple angles between 0 and 90 degree, thereby faceting. This faceting may allow the expansion to be staged by tactile feedback. In still other embodiments, the ramped surface is curved and has a radius of between 0 and 1.0 inches. In other embodiments, there may be multiple radii. The ramped surface may be located on other surfaces ofbendable member118.Gripper108 may have 1, 2, 3, 4, 5, 6, or some number ofbendable members118 that can be accommodated by the geometry of the device. In some embodiments,gripper108 may be made of a nickel-titanium alloy.

FIGS. 8A and 8B show detailed features ofproximal gripper109.Proximal gripper109 has a construction and operation similar to those ofdistal gripper108.Gripper109 includes two pairs of opposingbendable members118′. Eachbendable member118′ has a thinnedportion120′ that connects it to acommon collar810. Thinnedportions120′ permit bending as the opposite distal ends122′ ofmembers118′ are urged radially outward, such thatmembers118′ may pivot about thinnedportions120′. When radially extended, distal ends122′ ofbendable members118′ contact the inside of the bone to anchor the distal portion ofdevice100 to the bone, as will be later described. As shown, eachdistal end122′ includes a rampedsurface812 to assist in radial deployment. In some embodiments rampedsurface812 is omitted. In other embodiments, it has an angle selected between 0 and 90 degrees. In still other embodiments, the ramped surface is curved and has a radius of between 0 and 1.0 inches. The ramped surface may be located on other surfaces ofbendable member118′. In some embodiments,gripper109 may be made of a nickel-titanium alloy. In some embodiments, one or more grippers may eachcomprise 1, 2, 3, 4, 5, 6 or more bendable members similar tomembers118 or118′ shown. In some embodiments,gripper109 may be made of a nickel-titanium alloy.

FIGS. 9 and 10 show longitudinal cross-sections ofdevice100 with its components fully assembled as previously described.FIG. 9 showsdevice100 in a retracted state, whileFIG. 10shows device100 in a deployed state. To deploygrippers108 and109, a driver tool, such as one with a hexagonal tip (not shown) is inserted be axially into theproximal end102 ofdevice100 until the tool tip is received within keyedsocket130 ofdrive member128. When the driver tool is axially rotated, threadably engageddrive member128 andactuator126 are drawn together (i.e.drive member128 moves left toward thedistal end104 andactuator126 moves right toward theproximal end102 of device100). In alternative embodiments, a barbed, serrated wire may be used instead ofactuator126, and it may be ratcheted through a mating drive member. In an alternative embodiment,actuator126 may be made of a super elastic alloy that when released from its insertion state it returns to its unstressed state thereby drivinggrippers108 and109 outward, shortening the device thereby compressing518 into a rigid state.

During this actuation,bendable members118 ofproximal gripper108 are urged radially outward by a ramped surface onactuator head124.Actuator head124 is formed on the distal end ofactuator126 and contacts rampedsurfaces712 on the distal ends ofbendable members118. Asactuator head124 is drawn proximally, thinnedportions120 bend and allowbendable members118 to pivot outwardly through slots indistal body member518.Gripper108 and theactuator head124 may be reversed in their geometrical layout of the device. Thegripper108 may be drawn by theactuator126 over theactuator head124, thereby deflecting the bendable members,118, outward. Similarly, the bendable members,118, may be made of a super elastic or elastic or spring alloy of metal whereby the bendable members are predisposed in their set state in the insertion configuration, that being their smallest diameter. When the actuator head,124, engages the super elastic, elastic or spring alloy of steelbendable members118, a continuous force is imparted uponactuator head124 such that thebendable members118 return to their insertion geometry after theactuator head124 is removed. Typical super elastic, elastic, or spring alloys of metals include spring steels and NiTi or nitinol. Conversely,bendable members118 may be made of super elastic, elastic, or spring alloys of metal and set in their maximum outside diameter, in their deployed state.Actuator124 and the rectangular apertures in518 would work cooperatively to expose thebendable members118. Since thebendable members118 would be set in their maximum outside dimension and constrained within518, upon exposure of118 to the rectangular apertures, the bendable members would be driven by the material properties into the bone.

At generally the same time that gripper108 is being deployed,drive member128 is moving distally, carryingproximal gripper109 with it. This motion drives the rampedsurfaces812 at the end ofbendable members118′ against the ramped surfaces614 on the ends of T-shapedappendages612 ofcoupling member516, thereby urging the distal ends122′ ofbendable members118′ radially outward. Asgripper109 continues to move distally, thinnedportions120′ bend and allowbendable members118′ to pivot outwardly through slots inproximal body member510.Gripper109 and thecoupling member516 may be reversed in their geometrical layout of the device. Thegripper109 may be drawn by thedrive member128 over thecoupling member516, thereby deflecting the bendable members,118′, outward. Similarly, the bendable members,118′, may be made of a super elastic or elastic or spring alloy of metal where by the bendable members are predisposed in their set state in the insertion configuration, that being their smallest diameter. When thecoupling member516, engages the super elastic, elastic or spring alloy of steel bendable members,118′, a continuous force is imparted uponcoupling member516 such that thebendable members118, return to their insertion geometry after thecoupling member516 is removed. Typical super elastic, elastic, or spring alloys of metals include spring steels and NiTi or nitinol. Conversely,bendable members118′ may be made of super elastic, elastic, or spring alloys of metal and set in their maximum outside diameter, in their deployed state. Couplingmember516 and the rectangular apertures in510 would work cooperatively to expose thebendable members118′. Since thebendable members118′ would be set in their maximum outside dimension and constrained within510, upon exposure of118′ to the rectangular apertures, the bendable members would be driven by the material properties into the bone.

It can be seen inFIG. 9 thatbushing514 initially prevents T-shapedappendages612 from collapsing radially inward. However, asdrive member128 carries bushing514 far enough towarddistal end104, bushing514 lines up with the circumferential portions of T-shaped slots610 (shown inFIGS. 6A and 6B) and the necked downportions616 of T-shapedappendages612. Oncebushing514 has advanced this far distally, T-shapedappendages612 are permitted to bend at necked downportions616 and collapse radially inward asgripper109 continues to advance distally. An advantage to this arrangement is that is allowsgrippers108 and109 to initially anchor themselves within the intramedullary cavity of the bone before T-shapedappendages612 are permitted to collapse. Further rotation ofdrive member128 allowsbendable members118′ to further advance in the distal direction (by collapsing T-shaped appendages612) rather than being forced to continue to expand only in the radial direction. This two-stage action allowsgrippers108 and109 to anchor on opposite sides of a bone fracture and then move closer together to approximate the fracture.

As previously mentioned,device100 may include one or more flexible-to-rigid body portions114. This feature is flexible upon entry into bone and rigid upon application of compressive axial force provided by tensioningactuator126. Various embodiments may be used, including dual helical springs whose inner and outer tubular components coil in opposite directions, a chain of ball bearings with flats or roughened surfaces, a chain of cylinders with flats, features, cones, spherical or pointed interdigitating surfaces, wavy-helical cut tubes, two helical cut tubes in opposite directions, linear wires with interdigitating coils, and bellows-like structures. The flexible to rigid bodies may have a polygonal cross sectional geometry having any suitable number of sides from 1 to infinity. The flexible-to-rigid body may be cut in a specific way so that upon activation it conforms to a specific shape. The resultant shape may resemble or match the original anatomical shape of the bone. The resultant shape may provide specific translational actions so as to improve the healing of bone or create a resultant bone-implant construct that promotes a desired resultant geometry or effect. These resultant geometries may be bone lengthening where growth of the bone is improper, bone rotation to remediate poor pronation, supination, deflection, extension, deviation, or inclination of an appendage or joint. The shape of the flexible-to-rigid body may be devised or designed from x-ray or CT scans of the contralateral unaffected anatomy to return the affected anatomy to its original anatomical configuration or match the existing contralateral configuration.

The design of the flexible-to-rigidtubular body portion114 allows a single-piece design to maximize the transformation of the same body from a very flexible member that minimizes strength in bending to a rigid body that maximizes strength in bending and torque. The flexible member transforms to a rigid member when compressive forces are applied in the axial direction at each end, such as by an actuator. Thebody portion114 is made, for example as shown inFIG. 3, by a near-helical cut116 on a tubular member at an angle of incidence to the axis somewhere between 0 and 180 degrees from the longitudinal axis of thetubular body portion114. The near-helical cut or wavy-helical cut may be formed by the superposition of a helical curve added to a cyclic curve that produces waves of frequencies equal or greater than zero per turn around the circumference and with cyclic amplitude greater than zero. The waves of one segment nest with those on either side of it, thus increasing the torque, bending strength and stiffness of the tubular body when subjective to compressive forces. The tapered surfaces formed by the incident angle allow each turn to overlap with the segment on either side of it, thus increasing the bending strength when the body is in compression. Additionally, the cuts can be altered in depth and distance between the cuts (i.e. thickness) on the longitudinal axis along the length ofbody portion114 to variably alter the flexible-to-rigid characteristics of the tubular body along its length. As shown inFIG. 15 or16 for example, thebody portion114 is made by apatterned cut116′. The pattern may be a repeating pattern, or it may be a non repeating pattern as shown in the Figures. As shown inFIG. 16, thepatterned cut116′ may include a ramp142, edges144, and inter-digitations146 (i.e. portions that are interlocking). The ramp142 may function to dictate the radius of curvature and/or the chord length of the geometry of the elongate body in its rigid state. The ramp may be sized and configured such that the geometry in the rigid shape fits or matches the anatomical curvature of the specific bone into which it will be implanted. The edges144 may function to prevent axial displacement or excessive elongation of the elongate body. The edges may function to prevent the elongate body from unraveling and allow for the removal of the device. In some embodiments, the edges may be sized and configured to withstand up to about 200 pounds-force. The inter-digitations146 may also function to prevent axial displacement or excessive elongation of the elongate body and in some instances, they may provide torsional resistance, especially when the elongate body is curved and in a rigid state.

Thecuts116 inbody portion114 allow an otherwise rigid member to increase its flexibility to a large degree during deployment. The tubular member can have constant or varying internal and external diameters. This design reduces the number of parts of the flexible-to-rigid body portion of the device and allows insertion and extraction of the device through a curved entry port in the bone while maximizing its rigidity once inserted. Application and removal of compressive forces provided by a parallel member such as wire(s), tension ribbons, a sheath, oractuator126 as shown will transform the body from flexible to rigid and vice versa.

In operation, asactuator126 is tightened,gripper members118 and118′ are extended radially outwardly. Once the distal ends ofgripper members118 contact bone and stop moving outward, continued rotation ofactuator126 drawsgrippers108 and109 together, as previously described, and also draws theproximal end102 and thedistal end104 ofdevice100 closer together untilcuts116 are substantially closed. As this happens,body portion114 changes from being flexible to rigid to better secure the bone fracture(s), as will be further described below. Rotatingactuator126 in the opposite direction causesbody portion114 to change from a rigid to a flexible state, such as for removingdevice100 if needed in the initial procedure or during a subsequent procedure after the bone fracture(s) have partially or completely healed.Body portion114 may be provided with a solid longitudinal portion136 (as seen inFIGS. 3 and 4) such thatcuts116 are a series of individual cuts each traversing less than 360 degrees in circumference, rather than a single, continuous helical cut. Thissolid portion136 can aid in removal ofdevice100 by keepingbody portion114 from undesirably extending like a spring.

If removal ofdevice100 is desired,keeper ring512 also serves to help retractgripper109.Keeper ring512 pullsgripper109 in the proximal direction asdrive member128 moves proximally, and also asdevice100 is being with drawn, to keep gripper109 from sliding distally alongdrive member128. Withdrive member128 retracted to its original proximal position andactuator126 extended to its original distal position (as both shown inFIG. 9),bendable gripper members118,118′ are free to retract back withindistal body member518 andproximal body member510, respectively, asdevice100 is withdrawn from the bone in the proximal direction.

As shown inFIGS. 9 and 10,hub112 at theproximal end102 ofdevice100 may be provided with anangled hole174 for receiving a bone screw, interlocking pin, or transverse bone attachment member tofurther anchor device100 to a bone, as will be later described.Hole174 may be tapped to interfere with the bone screw, interlocking pin, or transverse bone attachment member so that there is mechanical interference between thehub112 and the attachment member, such that, over time, the attachment member does not back out or translate away or into the hub unexpectedly.Hub112 may also be provided with an internally threaded bore as shown. This threaded bore can serve to attach an insertion and removal tool (not shown) to aid in placing or removingdevice100 in the intramedullary space of a bone. A step may also be provided at the proximal end ofhub112 to mate with a similar step of the insertion tool to preventdevice100 from rotating with respect to the tool. The step can be semicircular or of any suitable geometrical configuration so that the insertion tool and hub are keyed relative to each other for alignment and secure positioning. After disengaging the tool fromdevice100, the threaded bore may also serve to receive an end plug (not shown) to prevent ingrowth of tissue into implanteddevice100.

FIGS. 11 and 12show device100 implanted in aright clavicle12.FIG. 11 showsclavicle12 from a superior perspective, whileFIG. 12 showsclavicle12 from a posterior perspective. As shown, the clavicle has a lateral segment having alateral end24 and a medial segment having amedial end20. In a patient, the lateral end is adjacent to the acromion of a scapula and the medial end is adjacent to the manubrium of a sternum. As shown inFIGS. 11 and 12, the lateral segment is between thefracture28 and thelateral end24 and the medial segment is between the fracture and themedial end20.

A method of implanting thedevice100 into a bone and of repairing the bone, such as a clavicle, may include the steps of creating anintramedullary channel132 and inserting the bone fixation device into the channel. The channel may be created such that the channel traverses thefracture28 of the bone and comprises at least one segment138 that substantially follows the anatomical contour of the bone. The bone fixation device may be inserted into the channel such that the device transverses the fracture and at least aportion114 of an elongate body of the fixation device in a flexible state is placed within the contoured segment of the channel. The method may further comprise the step of operating an actuator to deploy at least one gripper of the fixation device to engage an inner surface of the intramedullary channel to anchor the fixation device to the clavicle.

In a first embodiment, to implantbone fixation device100 inclavicle12, an incision is first made at thefracture28, and tissue is retracted if needed to access the fracture.Fracture28 is then distracted to gain access to the medial end of the lateral portion of the bone. A channel may then be drilled axially through the lateral portion of the bone fromfracture site28 outward toward thelateral end24 until it surfaces at the lateral end as shown. A guidewire, such as a K-wire, may first be driven anterior to posterior thereby tenting the posterior skin and the drill guided over the guidewire anterior to posterior in the lateral clavicle segment.

A second incision may be made where the channel exitslateral end24 ofclavicle12 in order to access the exit point. A guide wire may then be placed through the second incision and into the lateral exit point of the channel created in the lateral portion ofclavicle12. The guide wire may then be fed medially through the channel to thefracture site28. With the fracture approximated, the guide wire may be advanced across the fracture site and into the medial portion ofclavicle12. Note that the path of the guide wire may need to bend to approximately follow the longitudinal axis ofclavicle12. The procedure may be done under fluoroscopy or other imaging technique to allow the surgeon to visualize the path of the guide wire as it is advanced, and/or to confirm its location once extended throughclavicle12. A guiding sheath or cannulated drill bit may alternatively be used to facilitate the placement of the guide wire from anterior to posterior in the lateral clavicle fragment, thereby allowing the guide wire to be passed either anterior to posterior in the lateral fragment or posterior to anterior in the lateral fragment.

A canulated drill, reamer, or other channel forming instrument may then be advanced over the guide wire to create a straight or curved channel in the medial portion ofclavicle12 as needed. Once the desired intramedullary channel is created on both sides offracture28,device100 may be inserted into the channel through the lateral exit point.

As previously described,grippers108 and109 are in a retracted state during insertion, and flexible torigid body portion114 is in a flexible state. Withfracture28 roughly approximated,grippers108,109 may be deployed andbody portion114 converted to a rigid state by inserting a rotary drive tool through the second incision and intoproximal end102 ofdevice100, and rotating the tool as previously described. According to aspects of the invention, this action can further approximatefracture28. One ormore screws110 may be inserted in the second incision and throughhub112 as shown to further secureproximal end102 ofdevice100 to thelateral end24 ofclavicle12. At this point, any insertion tool attached todevice100 may be removed and replaced with an end plug if desired, and the incisions are closed.

In a second embodiment, to implantbone fixation device100 inclavicle12, an incision is first made at thefracture28. The patient may be positioned in the “beach chair” position or any other suitable position for surgery. The incision is made at the front (anterior side) of the patient adjacent to the fracture. Tissue is retracted if needed to access the fracture and thefracture28 may then be distracted or elevated to gain access to each of the segments of the bone. The medial segment and lateral segment are then both prepared for the insertion of the device by creating a channel within them.

Any suitable combination of tools may be used to create the channels in both the medial segment and the lateral segment of the clavicle. The tools may include hand tools or power tools. The tools may also include awls, drill bits, guidewires, or any other suitable tools to create a channel within bone. The awls may be curved awls, straight awls, and/or malleable awls (i.e. the user may change the radius of curvature of the awl intraoperatively). The tools may have any suitable head geometry such as a pointed geometry, a blunted geometry, a fluted geometry, etc. In some cases, a blunted tip is preferably over a sharp tip as to avoid important nerves (such as the bracheoplexus) and vessels (such as the subclavian artery which supplies blood to the brain) that surround the clavicle bone. The tools may be cannulated (i.e. hollow) or solid. In the case that the tool is cannulated, it may be adapted to be inserted into the bone over a guidewire and/or the tool may function as a sheath or trocar like device and a guidewire may be inserted through the cannula of the cannulated tool.

The segments may be prepared in any suitable order. As an example, the medial segment may be prepared first. The channel is created in the medial segment by inserting a tool into the medial segment starting at the fractured end. The tool is then moved through the medial segment creating the channel. The channel substantially follows the anatomical contour of the bone. In the case of the clavicle, as shown inFIG. 11, this means following the curve of the bone through the medial segment. A curved tool may be used to create the curved or contoured segment of the channel. A straight tool may be used to create the substantially straight segments before and/or after the curved or contoured segment. As shown inFIG. 12, thechannel132 is created substantially along the midline of the bone. Furthermore, thechannel132 may run deeper into the medial segment of the bone than conventional channels can because it is a curved channel. Conventional channels cannot be curved, and therefore they cannot be created past the curved portion or bend in the medial segment of the clavicle bone without breaking out of the bone.

As an example, once the medial segment is prepared, the lateral segment may be prepared by creating a channel through the lateral segment of the clavicle. The channel is created in the lateral segment by inserting a tool into the lateral segment starting at the fractured end. The tool is then moved through the lateral segment creating the channel. As shown inFIG. 11, the channel through the lateral segment may be substantially straight, and may exit the lateral segment of the clavicle toward thelateral end24 of the bone, creating aport140 through which other tools and/or the device can be inserted. As shown inFIG. 12, thechannel132 is created substantially along the midline of the bone.

As described above, any suitable combination of tools may be used to prepare the medial segment and then the lateral segment. For example, a smaller diameter channel may initially be created by a guidewire and/or an awl. The channel may be made larger by then inserting a larger diameter tool such as a larger awl, a drill bit, and/or a reamer. Once the initial channel is created in both the lateral and the medial segments, a guidewire may be inserted into the channels. The guidewire may be inserted through the incision such that a first end is inserted into the medial segment, and then a second end is inserted into the lateral segment. The second end may be inserted through the lateral segment such that it exits the bone at theport140. The guidewire may then “tent” or raise the skin of the patient at their back as the guidewire passes out of the bone. The guidewire may be used to puncture the skin at this point, or an additional incision may be made in the back of the patient, adjacent to the port at the lateral end of the bone. Alternatively, the incision at the back of the patient may be made first (or the guidewire may puncture the skin) and the guidewire may be inserted from the back of the patient, through the port, into the lateral segment of the bone, across the fracture, and into the medial segment of the bone. The fracture may be reduced (i.e. brought together) before or after the insertion of the guidewire. The fracture may be held together with conventional surgical bone clamps.

Once the guidewire is in place within thechannel132, tools may be inserted into the channel over the guidewire. For example, a cannulated reamer (stiff and/or flexible) or cannulated drill bit may be inserted throughport140 and into the clavicle by being threaded over the guidewire. A straight tool may be used to enlarge the diameter of the straight portions of the channel, and a curved or flexible tool may be used to enlarge the diameter of the curved and/or straight portions of the channel. The guidewire may function to guide the tools through the bone such that the tools follow the anatomical curvature of the bone (through at least a portion the medial segment), and stay substantially at the midline of the bone. In some instances, the initial channel of lateral segment will have a larger diameter than the initial channel of the medial segment, so tools may be used to only enlarge a portion (e.g. the medial segment) of the channel.

Additional tools may be inserted into the channel over the guidewire. For example, a depth gauge168, as shown inFIG. 24, may be inserted into the channel. In some embodiments, the depth gauge includes markings170 to indicate the depth of the channel created. The markings may be reverse scale markings such that the deeper that the gauge can be inserted into the channel, the higher the marking that will be legible. The depth reading may be used to determine the length of device needed to fit correctly within the channel. The flexible torigid body portion114 may rest substantially within the contoured portion138 of the channel and the end of the device is just below the outer surface of the bone. Various lengths and diameters of devices may be provided for the surgeon to select from to suit the particular anatomy and fracture involved. For example,device100 may be provided in 4, 5 and 6 mm diameters, and in 50, 75, 100 and 125 mm lengths. Dimensions and configurations can be altered for use in bones other than the clavicle.

The device may then be inserted through theport140 and positioned within theintramedullary channel132, as shown inFIGS. 11 and 12. In order to insert the device through the incision and the surrounding soft tissues, a tissue protection tool may be used. As shown inFIGS. 25-27, thetissue protection tool172 or172′ may function to guide the device through the soft tissue to the port while protecting the soft tissue from being damaged by the device. In some embodiments, as shown inFIGS. 26 and 27, the protection tool comprises a taperedportion174 at one end of the tool. The tapered portion may be sized and configured to fit at least partially within the entry port in the bone. The tapered portion may function to pilot or guide the fixation device into the channel in the bone. As shown inFIG. 25, the protection tool comprises a toothed portion176 at one end of the tool. The toothed portion may be sized and configured to fit at least partially within the entry port in the bone or may alternatively be sized and configured to grip the end of the bone. In some embodiments, as shown inFIG. 27, the protection tool has aU-shaped cross section178 that cradles the fixation device. Once the fixation device is in place and/or at least partially within the channel of the bone, the protection tool may simply be pulled off of the fixation device. In some embodiments, the fixation device may be sold or provided to a user already coupled to the protection tool. Alternatively, the protection tool may be sold or provided to a user coupled to a combination tool or other insertion, actuation, and/or alignment devices. The combination tool and insertion, actuation, and/or alignment devices are described in further detail in U.S. Provisional Application 61/060,445, filed 10 Jun. 2008. Once inserted, the device may be actuated to anchor the fixation device to the bone, as described above.

In an alternative method, the entire implant procedure may be performed through a single incision at thelateral end24 ofclavicle12. In this alternative procedure, a drill enters the lateral portion ofclavicle12 and is advanced to fracturesite28. A guide wire may then be advanced across the approximated fracture site and into the medial portion of the bone. A canulated drill or reamer may then be advanced over the guide wire to complete the intramedullary channel in the medial portion ofclavicle12.Device100 is then inserted and deployed and described above. This alternative method may be referred to as a “closed” procedure and requires more work and skill to perform, but is less invasive than the first method described. In any method, it is envisioned that the use of a guide wire may be omitted if desired, particularly ifdevice100 is deployed in a relatively straight portion of bone.

In an alternative variation of the “closed” procedure, once an incision is made adjacent to an end portion of the lateral segment of the clavicle, the channel may be created in a clavicle bone by inserting a tool or a series of tools through the incision and into the end portion of the lateral segment of the of the clavicle. As described above, a tool is inserted into the bone and advanced through the bone such that it traverses the fracture of the bone. The tool may be a guidewire. The guidewire has a stiffness such that it may traverse the fracture. For example, a guidewire with adequate stiffness to traverse the fracture may be one that is stiff enough to maintain a substantially straight trajectory through the midline of the bone, and one that will not buckle or otherwise bend or fail within the bone or across the fracture. Once a tool has been inserted into the bone and across the fracture, a second tool may be inserted to create the medial segment of the channel. The channel within the medial segment of the clavicle substantially follows the anatomical curvature or contour of the clavicle bone. Any suitable tool may be used to create this contoured segment of the channel. For example, a second guidewire may be inserted (in some cases, after the first guidewire is removed) into the clavicle at the lateral end and moved through the bone, following the anatomical curvature of the bone. The second guidewire is less stiff than the first guidewire such that it may flex and bend around the curvature of the clavicle and create an anatomically matching (i.e. curved) channel within the bone. Any number of guidewires having any combination of stiffnesses may be used sequentially to create the channel within the clavicle such that at least a portion of the channel matches the anatomical contour of the clavicle.

In an alternative example, a cannulated reaming tool or drill bit may be advanced into the bone over one of the guidewires described above. The cannulated tool may be used to expand the diameter of the channel to a diameter large enough to accept the fixation device. The cannulated tool may be stiff or flexible. For example, if the tool is flexible, it may be advanced over the guidewire and follow the curve of the channel to create a contoured and anatomically matching channel. The cannulated tool may also function as a sheath or trocar-like device. For example, the cannulated tool may remain at least partially within the bone, and one or a series of guidewires may be inserted and removed through the cannulated tool. Alternatively, the guidewire may be removed, and a tool (cannulated or not) may be moved through the bone independently.

FIGS. 13 and 14 show an alternative embodiment similar todevice100 described above.Device100′ includes adistal gripper108 but does not include a proximal gripper. Theproximal end102 ofdevice100′ is secured to the bone by one or more bone screws. For this purpose, three throughholes1310,1320 and1330 are provided inhub112′ at various angles. Hole1320 runs perpendicularly tohub112, and holes1310 and1330 on either side angle toward hole1320. The three holes share a common exit point, which is anelongated slot1340 on the opposite side ofhub112.FIG. 16, shown an embodiment similar to that ofFIGS. 13 and 14 that includes apatterned cut116′ as described above.

FIGS. 17 and 18 show another alternative embodiment similar todevice100 described above. Device1700 further includes a screw tip148. The screw tip may be sized and configured to screw into bone. Additionally, the screw tip may be sized and configured to be a self tapping screw tip. In some variations, as shown inFIG. 17, the device1700 may not need to include distal and/or proximal grippers due to the engagement of the screw tip into bone. Additionally, the flexible-to-rigid portion114 of the elongate body may function as the actuatable bone engaging mechanism (either alone or in addition to the screw tip) by gripping the bone as the elongate body is changed from its flexible state to its rigid state. In some embodiments, a channel is created in the bone prior to inserting device1700. The diameter of the channel may be about the same size as the major thread diameter of screw tip148, or may be about the same size as the minor diameter of screw tip148. In some embodiments, a proximal portion of the channel may be at least as large as the major diameter and a distal portion of the channel may be about the same size as the minor diameter. In other embodiments, little or no channel formation may be performed before inserting device1700 into the bone, relying instead on the turning screw tip148 to form its own channel as it is screwed into the bone. In some embodiments a guide wire is advanced into the bone first and device1700 then threaded over the guide wire.

Additionally, as shown inFIG. 18, the device may further includethreads150 along a portion of the inner diameter of the elongate body, wherein the threads are sized and configured to receive a compression screw152 (as shown inFIG. 17). The compression screw may function to compress the device1700 against the screw tip148 and/or to the inside walls of the channel within the bone. The compression screw may further function to approximate a fracture within the bone, in some instances by approximating the lateral segment of the bone (coupled to the compression screw) with the medial segment of the bone (coupled to the screw tip).

FIG. 18 also shows adrive member128′ positioned proximally to the flexible-to-rigid portion114 of the elongate body and threadably engaged (as shown by threads154) with theactuator126′. As shown, the actuator is disposed along the length of the device, and has a surface156 that couples to the distal end of the flexible-to-rigid portion114. To actuate the device, as an example, a driver tool, such as one with a hexagonal tip (not shown) may be inserted axially into the proximal end of the device until the tool tip is received within keyedsocket130′ ofdrive member128′. When the driver tool is axially rotated, threadably engaged drive member and the distal end of the actuator are drawn together such that they apply a compressive force to the flexible-to-rigid portion the elongate body along the longitudinal axis thereby changing the elongate body from its flexible state to its rigid state.

FIGS. 19 and 20 also show another alternative embodiment similar todevice100 described above. Device1900, likedevice100, includes adistal gripper108 and aproximal gripper109. In this embodiment, the flexible-to-rigid portion114 of the elongate body is disposed at a location on the elongate body distal to both the distal and proximal grippers.

FIG. 20 shows adrive member128″ positioned proximally to the flexible-to-rigid portion114 of the elongate body and threadably engaged (as shown by threads154′) with theactuator126″. As shown, the actuator is disposed along the length of the device, has a surface156′ that couples to the distal end of the flexible-to-rigid portion114, and has a surface158 that contacts thebendable member118 of thefirst gripper108. To actuate the device, as an example, a driver tool, such as one with a hexagonal tip (not shown) may be inserted axially into the proximal end of the device until the tool tip is received within keyedsocket130″ ofdrive member128″. When the driver tool is axially rotated, threadably engaged drive member and actuator are drawn together. The first surface of the actuator and the drive member are drawn together thereby applying a compressive force to at least a portion of the elongate body along the longitudinal axis changing the elongate body from its flexible state to its rigid state. Additionally, the second surface moves proximally against the bendable member, thereby pivoting the bendable member of the first gripper away from the longitudinal axis.

FIGS. 21-23 show yet another alternative embodiment similar todevice100 described above. Device2100 may not include a distal gripper or a proximal gripper, but rather the flexible-to-rigid portion114 of the elongate body may function as the actuatable bone engaging mechanism by gripping the bone as the elongate body is changed from its flexible state to its rigid state. The actuator of device2100 is a guidewire160.FIG. 22 shows how the elongate body is cannulated such that it is sized and configured to receive the guidewire160. As shown, the guidewire is disposed along the length of the device. As shown inFIG. 23, the guidewire160 includes adistal tip164, which includes a surface156″ that couples to the distal end of the flexible-to-rigid portion114. The guidewire also includes features such as a threaded portion166 and a flat portion162. The guidewire may further include any suitable combination of features such that it may function to actuate the flexible-to-rigid portion and/or an actuatable bone engaging mechanism.

As shown inFIGS. 22 and 23, device2100 also includes adrive member128′ positioned proximally to the flexible-to-rigid portion114 of the elongate body and threadably engaged with the guidewire160 (as shown by threaded portion154″ inFIG. 22). To actuate device2100, as an example, a driver tool, such as one with a hexagonal tip (not shown) may be inserted axially into the proximal end of the device until the tool tip is received within keyedsocket130″′ ofdrive member128″′. When the driver tool is axially rotated, threadably engaged drive member and guidewiredistal tip164 are drawn together such that the surface156″ applies a compressive force to the flexible-to-rigid portion the elongate body along the longitudinal axis and thereby changes the elongate body from its flexible state to its rigid state.

In some embodiments, a guide wire1350 (FIG. 13) may be used to penetrate the bone prior to insertingdevice100′. A cannulated reamer and/or drill can be used over the guide wire to create an intramedullary space for the device.Device100′ can then be guided into place overguide wire1350. In other embodiments, the intramedullary space may be prepared anddevice100′ inserted without the use of a guidewire.

In accordance with the various embodiments of the present invention, the device may be made from a variety of materials such as metal, composite, plastic or amorphous materials, which include, but are not limited to, steel, stainless steel, cobalt chromium plated steel, titanium, nickel titanium alloy (nitinol), superelastic alloy, and polymethylmethacrylate (PMMA). The device may also include other polymeric materials that are biocompatible and provide mechanical strength, that include polymeric material with ability to carry and delivery therapeutic agents, that include bioabsorbable properties, as well as composite materials and composite materials of titanium and polyetheretherketone (PEEK™), composite materials of polymers and minerals, composite materials of polymers and glass fibers, composite materials of metal, polymer, and minerals.

Within the scope of the present invention, each of the aforementioned types of device may further be coated with proteins from synthetic or animal source, or include collagen coated structures, and radioactive or brachytherapy materials. Furthermore, the construction of the supporting framework or device may include radio-opaque markers or components that assist in their location during and after placement in the bone or other region of the musculo-skeletal systems.

Further, the reinforcement device may, in one embodiment, be osteo incorporating, such that the reinforcement device may be integrated into the bone.

In a further embodiment, there is provided a low weight to volume device deployed in conjunction with other suitable materials to form a composite structure in-situ. Examples of such suitable materials may include, but are not limited to, bone cement, high density polyethylene, Kapton™, polyetheretherketone (PEEK), and other engineering polymers.

Once deployed, the device may be electrically, thermally, or mechanically passive or active at the deployed site within the body. Thus, for example, where the device includes nitinol, the shape of the device may be dynamically modified using thermal, electrical or mechanical manipulation. For example, the nitinol device may be expanded or contracted once deployed, to move the bone or other region of the musculo-skeletal system or area of the anatomy by using one or more of thermal, electrical or mechanical approaches.

It is contemplated that the inventive implantable device, tools and methods may be used in many locations within the body. Where the proximal end of a device in the anatomical context is the end closest to the body midline and the distal end in the anatomical context is the end further from the body midline, for example, on the humerus, at the head of the humerus (located proximal, or nearest the midline of the body) or at the lateral or medial epicondyle (located distal, or furthest away from the midline); on the radius, at the head of the radius (proximal) or the radial styloid process (distal); on the ulna, at the head of the ulna (proximal) or the ulnar styloid process (distal); for the femur, at the greater trochanter (proximal) or the lateral epicondyle or medial epicondyle (distal); for the tibia, at the medial condyle (proximal) or the medial malleolus (distal); for the fibula, at the neck of the fibula (proximal) or the lateral malleoulus (distal); the ribs; the clavicle; the phalanges; the bones of the metacarpus; the bones of the carpus; the bones of themetatarsus; the bones of the tarsus; the sternum and other bones, the device may be adapted and configured with adequate internal dimension to accommodate mechanical fixation of the target bone and to fit within the anatomical constraints. As will be appreciated by those skilled in the art, access locations other than the ones described herein may also be suitable depending upon the location and nature of the fracture and the repair to be achieved. Additionally, the devices taught herein are not limited to use on the long bones listed above, but can also be used in other areas of the body as well, without departing from the scope of the invention. It is within the scope of the invention to adapt the device for use in flat bones as well as long bones.

FIGS. 28 and 29 are perspective views of an embodiment of abone fixation device3100 having a proximal end3102 (nearest the surgeon) and a distal end3104 (further from surgeon) and positioned within the bone space of a patient according to the invention. In this example,device3100 is shown implanted in the upper (or proximal) end of anulna3106. The proximal end and distal end, as used in this context, refers to the position of an end of the device relative to the remainder of the device or the opposing end as it appears in the drawing. The proximal end can be used to refer to the end manipulated by the user or physician. The distal end can be used to refer to the end of the device that is inserted and advanced within the bone and is furthest away from the physician. As will be appreciated by those skilled in the art, the use of proximal and distal could change in another context, e.g. the anatomical context in which proximal and distal use the patient as reference, or where the entry point is distal from the surgeon.

When implanted within a patient, the device can be held in place with suitable fasteners such as wire, screws, nails, bolts, nuts and/or washers. Thedevice3100 is used for fixation of fractures of the proximal or distal end of long bones such as intracapsular, intertrochanteric, intercervical, supracondular, or condular fractures of the femur; for fusion of a joint; or for surgical procedures that involve cutting a bone. Thedevices3100 may be implanted or attached through the skin so that a pulling force (traction may be applied to the skeletal system).

In the embodiment shown inFIG. 28, the design of themetaphyseal fixation device3100 depicted is adapted to provide a bone engaging mechanism orgripper3108 adapted to engage target bone of a patient from the inside of the bone. As configured for this anatomical application, the device is designed to facilitate bone healing when placed in the intramedullary space within a post fractured bone. Thisdevice3100 has agripper3108 positioned distally and shown deployed radially outward against the wall of the intramedullary cavity. On entry into the cavity,gripper3108 is flat and retracted (FIG. 30). Upon deployment,gripper3108 pivots radially outward and grips the diaphyseal bone from the inside of the bone. One ormore screws3110 placed through apertures through thehub3112 lock thedevice3100 to the metaphyseal bone. Hence, the metaphysis and the diaphysis are joined. A flexible-to-rigid body portion3114 may also be provided, and in this embodiment is positioned betweengripper3108 andhub3112. It may be provided withwavy spiral cuts3116 for that purpose, as will be described in more detail below.

FIG. 30 shows a longitudinal cross-section ofdevice3100 in a non-deployed configuration. In this embodiment,gripper3108 includes two pairs of opposing bendablegripping members3118. Two of the bendablegripping members3118 are shown inFIG. 30, while the other two (not shown inFIG. 30) are located at the same axial location but offset by 90 degrees. Each bendable grippingmember3118 has a thinnedportion3120 that permits bending as the oppositedistal end3122 ofmember3118 is urged radially outward, such thatmember3118 pivots about thinnedportion3120. When extended,distal ends3122 ofbendable members3118 contact the inside of the bone to anchor the distal portion ofdevice3100 to the bone. In alternative embodiments (not shown), the gripper may comprise 1, 2, 3, 4, 5, 6 or more bendable members similar tomembers3118 shown.

During actuation,bendable members3118 ofgripper3108 are urged radially outward by a ramped surface onactuator head3124.Actuator head3124 is formed on the distal end ofactuator3126. The proximal end ofactuator3126 is threaded to engage a threaded bore ofdrive member3128. The proximal end ofdrive member3128 is provided with akeyed socket3130 for receiving the tip of a rotary driver tool3132 (shown inFIG. 32) through the proximal bore ofdevice3100. Asrotary driver tool3132 turnsdrive member3128,actuator3126 is drawn in a proximal direction to outwardly actuategripper members3118.

Ahemispherical tip cover3134 may be provided at the distal end of the device as shown to act as a blunt obturator. This arrangement facilitates penetration of bone (e.g. an intramedullary space) bydevice3100 while keeping the tip ofdevice3100 from digging into bone during insertion.

As previously mentioned,device3100 may include one or more flexible-to-rigid body portions3114. This feature is flexible upon entry into bone and rigid upon application of compressive axial force provided by tensioningactuator3126. Various embodiments of a flexible-to-rigid portion may be used, including dual helical springs whose inner and outer tubular components coil in opposite directions, a chain of ball bearings with flats or roughened surfaces, a chain of cylinders with flats, features, cones, spherical or pointed interdigitating surfaces, wavy-helical cut tubes, two helical cut tubes in opposite directions, linear wires with interdigitating coils, and bellows-like structures.

The design of the flexible-to-rigidtubular body portion3114 allows a single-piece design to maximize the transformation of the same body from a very flexible member that minimizes strength in bending to a rigid body that maximizes strength in bending and torsion. The flexible member transforms to a rigid member when compressive forces are applied in the axial direction at each end, such as by an actuator similar to3126. Thebody portion3114 is made, for example, by a near-helical cut3116 on a tubular member at an angle of incidence to the axis somewhere between 0 and 180 degrees from the longitudinal axis of thetubular body portion3114. The near-helical cut or wavy-helical cut may be formed by the superposition of a helical curve added to a cyclic curve that produces waves of frequencies equal or greater than zero per turn around the circumference and with cyclic amplitude greater than zero. The waves of one segment nest with those on either side of it, thus increasing the torque, bending strength and stiffness of the tubular body when subjective to compressive forces. The tapered surfaces formed by the incident angle allow each turn to overlap or interdigitate with the segment on either side of it, thus increasing the bending strength when the body is in compression. Additionally, the cuts can be altered in depth and distance between the cuts on the longitudinal axis along the length ofbody portion3114 to variably alter the flexible-to-rigid characteristics of the tubular body along its length.

Thecuts3116 inbody portion3114 allow an otherwise rigid member to increase its flexibility to a large degree during deployment. The tubular member can have constant or varying internal and external diameters. This design reduces the number of parts of the flexible-to-rigid body portion of the device and allows insertion and extraction of the device through a curved entry port in the bone while maximizing its rigidity once inserted. Application and removal of compressive forces provided by a parallel member such as wire(s), tension ribbons, a sheath, wound flexible cable, oractuator3126 as shown will transform the body from flexible to rigid and vice versa.

In operation, asactuator3126 is tightened,gripper members3118 are extended radially outwardly. Once the distal ends ofgripper members3118 contact bone and stop moving outward, continued rotation ofactuator3126 draws theproximal end3102 and thedistal end3104 ofdevice3100 closer together untilcuts3116 are substantially closed. As this happens,body portion3114 changes from being flexible to rigid to better secure the bone fracture(s), as will be further described below. Rotatingdrive member3128 in the opposite direction causesbody portion3114 to change from a rigid to a flexible state, such as for removingdevice3100 if needed in the initial procedure or during a subsequent procedure after the bone fracture(s) have partially or completely healed.Body portion3114 may be provided with a solid longitudinal portion3136 (as seen inFIGS. 30 and 36) such thatcuts3116 are a series of individual cuts each traversing less than 360 degrees in circumference, rather than a single, continuous helical cut. Thissolid portion3136 can aid in removal ofdevice3100 by keepingbody portion3114 from extending axially like a spring.

FIG. 31 illustrates acombination tool3138 useful for insertingdevice3100, actuatinggripper3108, compressing flexible-to-rigid body portion3114, approximating the fracture inbone3106, aligning anchor screw(s)3110, and removingdevice3100, if desired. In this exemplary embodiment,tool3138 includes an L-shapedbody3140 that mounts the other components of the tool and also serves as a handle. The main components oftool3138 are adevice attachment portion3142, arotary driver3132, an approximatingdriver3144, and ascrew alignment portion3146.

FIG. 32 shows a cross-section of thetool3138 anddevice3100 illustrated inFIG. 31. As shown,device attachment portion3142 includes aknob3148 rigidly coupled to atube3150 which is rotatably mounted withinsleeve3152.Sleeve3152 in turn is fixedly mounted totool body3140. The distal end oftube3150 is provided with external threads for engaging the internal threads on the proximal end ofdevice3100. As seen inFIG. 31, both the distal end ofsleeve3152 and the proximal end ofdevice3100 may be provided with semicircular steps that inter-engage to preventdevice3100 from rotating with respect tosleeve3152. With this arrangement,device3100 can be prevented from rotating when it is secured totool3138 bytube3150 ofdevice attachment portion3142. The mating semicircular steps also serve to positiondevice3100 in a particular axial and angular orientation with respect totool3138 for aligning screws with screw holes, as will be later described.

Rotary driver3132 may be used to actuategripper3108 and compress flexible-to-rigid body portion3114 afterdevice3100 is inserted intobone3106.Driver3132 may also be used to allowbody portion3114 to decompress and gripper3108 to retract if removal ofdevice3100 frombone3106 is desired. In the embodiment shown,driver3132 includesknob3154, torsion spring3156,hub3158,bushing3160 andshaft3162. The distal end ofshaft3162 is provided with amating tip3164, such as one having a hex-key shape, for engaging with keyedsocket3130 of device3100 (seen inFIG. 30), such that turningdriver shaft3162 turnsdrive member3128 and axially actuatesactuator3126, as described above.

The proximal end ofshaft3162 may be fitted with abushing3160, such as with a press-fit.Hub3158 may be secured overbushing3160, such as with a pin throughbushing3160 andshaft3162. In this embodiment,knob3154 is rotatably mounted overhub3158 andbushing3160 such thatknob3154 can rotate independently fromshaft3162. A torsion spring3156 may be used tocouple knob3154 tohub3158 as shown to create a torque limiting and/or torque measuring driver. With this indirect coupling arrangement, asknob3154 is rotated aboutshaft3162, spring3156 urgeshub3158 andshaft3162 to rotate in the same direction. Rotational resistance applied bydevice3100 toshaft tip3164 will increase in this embodiment asgripper3108 engagesbone3106, and flexible-to-rigid body portion3114 compresses. As more torque is applied toknob3154, it will advance rotationally with respect tohub3158 as torsion spring3156 undergoes more stress. Markings may be provided onknob3154 andhub3158 to indicate the torque being applied. In this manner, a surgeon can usedriver3132 to apply torque todevice3100 in a predetermined range. This can help ensure thatgripper3108 is adequately set inbone3106,body portion3114 is sufficiently compressed, and excessive torque is not being applied that might damagedevice3100,bone3106 or cause slippage therebetween. A slip clutch or other mechanism may be provided to allow the applied torque to be limited or indicated. For example,driver3132 may be configured to “click” into or out of a detent position when a desired torque is reached, thus allowing the surgeon to apply a desired torque without needing to observe any indicia on the driver. In alternative embodiments, the driver knob may be selectably or permanently coupled toshaft3162 directly.

Afterdevice3100 is inserted inbone3106 and deployed withtool3138 as described above, the approximatingdriver portion3144 oftool3138 may be used to compress one or more fractures inbone3106.Approximating driver3144 includesknob3166 located onsleeve3152.Knob3166 may be knurled on an outer circumference, and have threads on at least a portion of its axial bore. The internal threads ofknob3166 engage with mating external threads onsleeve3152 such that whenknob3166 is rotated it advances axially with respect tosleeve3152. Whendevice3100 is anchored inbone3106,sleeve3152 is prevented from moving away from the bone. Accordingly, asknob3166 is advanced axially towardbone3106, it serves to approximate bone fractures located betweengripper3108 andknob3166. Suitable thread pitch and knob circumference may be selected to allow a surgeon to supply a desired approximating force tobone3106 by using a reasonable rotation force onknob3166. In alternative embodiments (not shown), a torque indicating and/or torque limiting mechanism as described above may be incorporated into approximatingdriver3144.

As previously indicated,tool3138 may also include ascrew alignment portion3146. In the embodiment depicted in the figures,alignment portion3146 includes aremovable alignment tube3168 and twobores3170 and3172 throughtool body3140. In alternative embodiments (not shown), a single bore or more than two bores may be used, with or without the use of separate alignment tube(s).

In operation,alignment tube3168 is first received inbore3170 as shown. In this position,tube3168 is in axial alignment withangled hole3174 at thedistal end3102 ofdevice3100. As described above, the mating semicircular steps ofdevice3100 andsleeve3152 position angledhole3174 in its desired orientation. With this arrangement, a drill bit, screw driver, screw and/or other fastening device or tool may be inserted through the bore oftube3168 such that the device(s) are properly aligned withhole3174. The outward end ofalignment tube3168 may also serve as a depth guide to stop a drill bit, screw and/or other fastener from penetratingbone3106 beyond a predetermined depth.

Alignment tube3168 may be withdrawn frombore3170 as shown, and inserted inbore3172. In this position,tube3168 aligns withhole3176 ofdevice3100. As described above, a drill bit, screw driver, screw and/or other fastening device may be inserted through the bore oftube3168 such that the device(s) are properly aligned withhole3176.

FIG. 33 showsalignment tube3168 oftool3138 aligningscrew3110 withangled hole3174 at the distal end ofdevice3100, as described above.

FIG. 34A shows afirst screw3110 received throughangled hole3174 and asecond screw3110 received throughhole3176 indevice3100 and intobone3106.Screws3110 may be installed manually or with the aid oftool3138 as described above. The heads ofscrews3110 may be configured to be self-countersinking such that they remain substantially beneath the outer surface of the bone when installed, as shown, so as to not interfere with adjacent tissue. In this embodiment, theproximal end3102 ofdevice3100 is secured tobone3106 with twoscrews3110, and thedistal end3104 is secured bygripper3108. In this manner, any bone fractures located between theproximal screw3110 anddistal gripper3108 may be approximated and rigidly held together bydevice3100. In alternative embodiments (not shown), more than one gripper may be used, or only screws or other fasteners without grippers may be used to securedevice3100 withinbone3106. For example, the device shown inFIG. 28 could be configured with a second gripper located betweenscrew3110 and the middle of the device if the fracture is located more at the mid-shaft of the bone. Similarly, more than two screws or other fasteners may be used, or only grippers without fasteners may be used. In various embodiments, holes such as3174 and3176 as shown and described above can be preformed in the implantable device. In other embodiments, some or all of the holes can be drilled or otherwise formed in situ after the device is implanted in the bone.

Oncedevice3100 is secured withinbone3106,combination tool3138 may be removed by turningknob3148 to disengage threads oftube3150 from threads within theproximal end3102 ofdevice3100. An end plug3178 may be threaded into theproximal end3102 ofdevice3100 to preventing growth of tissue into implanteddevice3100.Device3100 may be left inbone3106 permanently, or it may be removed by performing the above described steps in reverse. In particular, plug3178 is removed,tool3138 is attached, screws3110 are removed,gripper3108 is retracted, anddevice3100 is pulled out usingtool3138.

FIG. 34B shows an alternative embodiment of acombination tool3138′ useful for insertingdevice3100, actuatinggripper3108, compressing flexible-to-rigid body portion3114, approximating the fracture inbone3106, aligning anchor screw(s)3110, and removingdevice3100, if desired. Liketool3138 described above,exemplary tool3138′ includes an L-shapedbody3140′ that mounts the other components of the tool and also serves as a handle. The main components oftool3138′ are adevice attachment portion3142, arotary driver3132, an approximatingdriver3144, and ascrew alignment portion3146. These components are constructed and function in a similar fashion to the components oftool3138 described above.Tool3138′ is constructed to allow one or more screw holes to be formed in vivo, and/or allow screw(s) to be aligned with such screw holes or preformed screw holes, through flexible-to-rigid body portion3114 ofdevice3100.Tool3138′ may be configured to allow the screw hole(s) may be formed at an angle throughbody portion3114, and/or formed perpendicularly to the longitudinal axis ofdevice3100.Tool3138′ may also include the capability to form screw holes or align screws for insertion in the proximal hub portion ofdevice3100 as described above.

Tool3138′ may be used to form screw hole(s) in flexible-to-rigid body portion3114 by guiding a drill bit withalignment tube3168. Screw hole(s) may also be formed directly inbody portion3114 without pre-forming or drilling holes in vivo, but by placing a screw directly intobody portion3114, such as with a self-tapping screw guided withalignment tube3168.

Internal components withindevice3100, such asactuator3126, may be configured such that screw(s) pass though it or pass around it. For example, in some embodiments the actuator comprises one or more cables, leaving enough room withinbody portion3114 so that a screw can avoid the actuator(s), or move it/them out of the way when passing into or throughbody portion3114. In some embodiments, the one or more actuators are large enough to allow one or more screws to pass through it/them without impeding the operation of the actuator(s). In some embodiments, the screw(s) only enter one wall oftubular body portion3114 without entering the interior space of the body portion.

FIGS. 35 and 36 show alternative embodiments similar todevice3100 described above.Device3100′ shown inFIG. 35 is essentially identical todevice3100 described above but is shorter in length and utilizes asingle anchor screw3110 at itsproximal end3102.Device3100″ shown inFIG. 36 is similar todevice3100′, but is shorter still. In various embodiments, the devices may be configured to have a nominal diameter of 3 mm, 4 mm, 5 mm or 6 mm. It is envisioned that all threedevice designs3100,3100′ and3100″ may each be provided in all three diameters such that the chosen device is suited for the particular fracture(s) and anatomy in which it is implanted.

In accordance with the various embodiments of the present invention, the device may be made from a variety of materials such as metal, composite, plastic or amorphous materials, which include, but are not limited to, steel, stainless steel, cobalt chromium plated steel, titanium, nickel titanium alloy (nitinol), superelastic alloy, and polymethylmethacrylate (PMMA). The device may also include other polymeric materials that are biocompatible and provide mechanical strength, that include polymeric material with ability to carry and delivery therapeutic agents, that include bioabsorbable properties, as well as composite materials and composite materials of titanium and polyetheretherketone (PEEK), composite materials of polymers and minerals, composite materials of polymers and glass fibers, composite materials of metal, polymer, and minerals.

Within the scope of the present invention, each of the aforementioned types of device may further be coated with proteins from synthetic or animal source, or include collagen coated structures, and radioactive or brachytherapy materials. Furthermore, the construction of the supporting framework or device may include radio-opaque markers or components that assist in their location during and after placement in the bone or other region of the musculo-skeletal systems.

Further, the reinforcement device may, in one embodiment, be osteo incorporating, such that the reinforcement device may be integrated into the bone. In a further embodiment, there is provided a low weight to volume device deployed in conjunction with other suitable materials to form a composite structure in-situ. Examples of such suitable materials may include, but are not limited to, bone cement, high density polyethylene, Kapton™, polyetheretherketone (PEEK), and other engineering polymers.

Once deployed, the device may be electrically, thermally, or mechanically passive or active at the deployed site within the body. Thus, for example, where the device includes nitinol, the shape of the device may be dynamically modified using thermal, electrical or mechanical manipulation. For example, the nitinol device may be expanded or contracted once deployed, to move the bone or other region of the musculo-skeletal system or area of the anatomy by using one or more of thermal, electrical or mechanical approaches.

It is contemplated that the inventive implantable device, tools and methods may be used in many locations within the body. Where the proximal end of a device in the anatomical context is the end closest to the body midline and the distal end in the anatomical context is the end further from the body midline, for example, on the humerus, at the head of the humerus (located proximal, or nearest the midline of the body) or at the lateral or medial epicondyle (located distal, or furthest away from the midline); on the radius, at the head of the radius (proximal) or the radial styloid process (distal); on the ulna, at the head of the ulna (proximal) or the ulnar styloid process (distal); for the femur, at the greater trochanter (proximal) or the lateral epicondyle or medial epicondyle (distal); for the tibia, at the medial condyle (proximal) or the medial malleolus (distal); for the fibula, at the neck of the fibula (proximal) or the lateral malleoulus (distal); the ribs; the clavicle; the phalanges; the bones of the metacarpus; the bones of the carpus; the bones of themetatarsus; the bones of the tarsus; the sternum and other bones, the device may be adapted and configured with adequate internal dimension to accommodate mechanical fixation of the target bone and to fit within the anatomical constraints. As will be appreciated by those skilled in the art, access locations other than the ones described herein may also be suitable depending upon the location and nature of the fracture and the repair to be achieved. Additionally, the devices taught herein are not limited to use on the long bones listed above, but can also be used in other areas of the body as well, without departing from the scope of the invention. It is within the scope of the invention to adapt the device for use in flat bones as well as long bones.

FIGS. 37A-37I show another embodiment of a bone fixation device constructed according to aspects of the invention.FIG. 37A is a perspective view showing theexemplary device3200 deployed in a fracturedclavicle3202.Device3200 is similar todevice3100 described above and shown inFIGS. 28-34A, but has agripper3204 located near its proximal end, anothergripper3206 located at a more distal location, and a flexible-to-rigid body portion3208 located near the distal end of the device. Abone screw3210 andgripper3204 are configured to securedevice3200 insidebone3202 on the proximal side offracture3212, while gripper3206 and flexible-to-rigid body portion3208 are configured to securedevice3200 on the distal side offracture3212. In other respects, construction and operation ofdevice3200 is much like that ofdevice3100 described above.

In this exemplary embodiment, each of the twogrippers3204 and3206 has four outwardly expandingarms3214. These arms are spaced at 90 degree intervals around the circumference of the device body. Thearms3214 ofgripper3204 may be offset by 45 degrees fromarms3214 ofgripper3206 as shown in the figures to distribute the forces applied bygrippers3204 and3206 on thebone3202. As shown inFIGS. 37E and 37F, asingle actuator3216 may be used to deploy bothgrippers3204 and3206.Actuator3216 may also be used to axially compress flexible-to-rigid body portion3208 to make it substantially rigid. At least a portion ofactuator3216 may be flexible to allow flexible-to-rigid body portion3208 to assume a curved shape, as seen inFIGS. 37A and 37B. Alternatively, it may be desirable in some embodiments to have flexible-to-rigid body portion3208 maintain a straight or a curved configuration regardless of whether it is in a flexible or rigid state. In these embodiments, the actuator may be rigid and faulted with the desired straight and/or curved shape to match the flexible-to-rigid body portion. In some embodiments, it may also be desirable to design at least a portion of the actuator with a high degree of axial elasticity to allow the actuator to continue to expand some gripper(s) and/or compress some flexible-to-rigid body portion(s) after other gripper(s) and/or flexible-to-rigid body portion(s) have already been fully deployed.

Referring toFIGS. 37G-37I, further details of anexemplary gripper3204 are shown.FIGS. 37G and37H show gripper3204 withbendable arms3214 in a retracted state. Ascam3218 ofactuator3216 is driven axially into the distal ramped ends ofarms3214,arms3214 bend at thinnedportions3220 to move radially outward toward the deployed position shown inFIG. 37I.Notches3222 may be provided in the distal ends ofarms3214 as shown to allowarms3214 to better grip interior bone surfaces. Without departing from the scope of the invention, one, two, three, or more bendable arms may be used.

Referring toFIGS. 38A-38D, another embodiment of a bone fixation device is shown.Device3300 includes acurved hub3302,proximal gripper3304, flexible-to-rigid body portion3306, anddistal gripper3308.Distal gripper3308 is similar in construction and operation to grippers3204 and3206 described above.Proximal gripper3304 is provided with three pairs ofscissor arms3310. Each pair ofarms3310 is pivotably interconnected at a mid-portion by a pin. Each arm is pivotably connected with a pin to eitherproximal end piece3312 ordistal end piece3314. Whenend pieces3312 and3314 are moved closer together,arms3310 pivot radially outward from an axially aligned retracted position, as shown inFIGS. 38A and 38C, to a deployed position, as shown inFIGS. 38B and 38D. In the deployed position, the distal ends of the sixarms3310 engage an inner surface of a bone as previously described.

In operation,device3300, withgrippers3304 and3308 in a retracted state, may be inserted into the intramedullary space within a bone, such as the radius.Device3300 may be inserted through a curved opening formed in the bone, such as an opening formed through a bony protuberance on a distal or proximal end or through the midshaft of the bone.Curved hub3302 may be configured with the same geometry of the curved opening in the bone, and when the flexible-to-rigid body portion3306 is in its flexible state, it can assume this same geometry. Oncedevice3300 is in place inside the bone, actuator3315 (shown inFIGS. 38C and 38D) may be actuated from the proximal end ofdevice3300 by turningdrive member3317 in a manner similar to that previously described. Longitudinal movement ofactuator3315 toward the proximal end ofdevice3300 causes flexible-to-rigid body portion3306 to foreshorten and assume its rigid state, and causesgrippers3304 and3308 to outwardly deploy against the bone. Bone screws may be inserted throughholes3316 shown incurved hub3302 to secure the proximal end ofdevice3300 to the bone. Further details of the construction and operation of a device similar todevice3300 may be found in co-pending U.S. application Ser. No. 11/944,366 filed Nov. 21, 2007 and entitled Fracture Fixation Device, Tools and Methods.

Device3300 is an example of an embodiment utilizing mixed gripper types. In other words, this device uses one scissors-arm tripod gripper3304 and one bendable-arm gripper3308. Other embodiments of the invention (not shown) use various combinations of gripper(s) and/or flexible-to-rigid body portion(s). Further exemplary gripper embodiments are described in detail in co-pending U.S. application Ser. No. 61/100,652 filed Sep. 26, 2008 and entitled Fracture Fixation Device, Tools and Methods. It is envisioned that virtually any combination of zero, one, two, or more grippers may be used in combination with zero, one, two or more flexible-to-rigid body portions to form a device adapted to a particular bone anatomy, fracture, disease state or fixation purpose. The grippers and/or flexible-to-rigid body portions may each be of identical or different construction, and may be placed together or at other locations along the device. Further, a straight, curved, flexible, rigid, or no hub at all may be used with the above combinations. Additionally, screws, K-wires, sutures or no additional fixation may be used with these various devices. The devices may be specially designed and constructed for a particular purpose or range of purposes. According to aspects of the invention, the components may also be designed to be interchangeable and/or produced in various sizes so that surgical kits may be provided. Such kits would allow surgical teams to select from a variety of components to build devices themselves, each suited to a particular patient's unique situation.

Referring toFIGS. 39A through 47B, further examples of the hubs discussed above are shown and will now be described.

FIGS. 39A-39F show details of acurved hub3400 similar tohub3302 illustrated inFIGS. 38A-38D. In this embodiment,hub3400 has an internally threaded portion at itsproximal end3402 for engaging with an insertion and removal tool as described above. (The proximal end is referenced as the end closest to the surgeon.) Theproximal end3402 may also have a keyed feature for mating with the tool for maintaining a desired orientation ofhub3400 relative to the tool.Hub3400 may also be provided with a counterbore at itsdistal end3404 for coupling to a gripper or flexible-to-rigid body portion, such as by press fit and/or welding.

Exemplary hub3400 includes threeholes3406,3408 and3410 through the wall thickness on its concave side, as seen inFIG. 39C. Similarly,hub3400 includes fourholes3412,3414,3416, and3418 through the wall thickness on its convex side, as seen inFIG. 39D. At least a portion of all seven holes may be seen inFIG. 39F.Holes3406 and3412 on opposite sides ofhub3400 are aligned to allow a bone screw to be inserted through the two holes across the hub to securehub3400 to the bone and/or to secure bone fragment(s) with the screw. Similarly, holes3408 and3414 are aligned to receive a second bone screw, and holes3410 and3416 are aligned to receive a third bone screw. A fourth screw may be inserted through the openproximal end3402 ofhub3400 and out throughhole3418. Each screw may be passed first through cortical bone, then cancellous bone, then through the two holes ofhub3400, through more cancellous bone and possibly into more cortical bone on the opposite side of the bone from where the screw entered.

In this embodiment, the holes ofhub3400 have a diameter of 2.4 mm. In other embodiments, the holes have a diameter of 2.7 mm. In still other embodiments, the holes may have larger or smaller diameters. The holes may be threaded during the fabrication ofhub3400, or threads may be formed in vivo. Various fixtures, jigs, tools and methods may be used to align the screws with the holes, such as a tool similar totool3138 shown inFIGS. 31-33 and described above. Further examples of positioning aids are provided in U.S. application Ser. No. 11/944,366 filed Nov. 21, 2007 and entitled Fracture Fixation Device, Tools and Methods. The heads of the screws may be countersunk into the bone as described in U.S. application Ser. No. 61/117,901 filed Nov. 25, 2008 and entitled Bone Fracture Fixation Screws, Systems and Methods of Use.

FIGS. 39G-39I illustrate an example how bone screws3420,3422,3424 may be inserted throughhub3400′ (which is similar to hub3400) as described above to secure the comminuted fracture depicted at the distal end of aradius bone3425. One, two, three, four, or more screws may be used depending on the anatomy and fracture condition of each particular case. It should be noted that in this particular embodiment, eitherscrew3422 or3424 may be placed throughhub3400′, but not both at the same time, as their paths intersect insidehub3400′. It can be seen that screws3422 and3424 extend acrossfracture3426 intobone fragment3428. Accordingly, eitherscrew3422 or3424 may be used toapproximate fracture3426 when the screw is tightened.

FIGS. 40A-40E show another exemplary embodiment of a bonefixation device hub3450.Hub3450 is of similar construction tohub3400 described above and includesproximal end3452 anddistal end3454. As seen inFIG. 40C,hub3450 includes fourholes3456,3458,3460, and3462 through the wall thickness on its concave side.Holes3456 and3458 are located the same longitudinal distance fromdistal end3454, but are symmetrically located on opposite sides of a central longitudinal plane. As can be seen, holes3456 and3458 actually overlap to form a single, figure-eight shaped hole.Holes3460 and3462 are also located the same longitudinal distance fromproximal end3452, and are symmetrically located on opposite sides of a central longitudinal plane.

As seen inFIG. 40D,hub3450 also includes sixholes3464,3466,3468,3470,3472, and3474 through the wall thickness on its convex side.Holes3464 and3466 are located the same longitudinal distance fromdistal end3454, but are symmetrically located on opposite sides of a central longitudinal plane.Holes3464 and3466 also overlap to form a single, figure-eight shaped hole, similar toholes3456 and3458 described above.Holes3468 and3470 are also located the same longitudinal distance fromproximal end3452, and are symmetrically located on opposite sides of a central longitudinal plane. Similarly, holes3472 and3474 are also located the same longitudinal distance fromproximal end3452, and are symmetrically located on opposite sides of a central longitudinal plane.

Holes3456 and3464 on diagonally opposite sides ofhub3450 are aligned to allow a bone screw to be inserted through the two holes across the hub, passing through a centerline ofhub3450. Similarly, holes3458 and3466 on diagonally opposite sides ofhub3450 are aligned to allow a bone screw to be inserted through the two holes across the hub, passing through a centerline ofhub3450. Since both of these two screw paths cross the centerline at the same location forming an X-pattern, only one screw may be placed through these two pairs ofholes3456/3464 and3458/3466 in any particular procedure.

In a similar manner, holes3460 and3468 on diagonally opposite sides ofhub3450 are aligned to allow a bone screw to be inserted through the two holes across the hub, passing through a centerline ofhub3450.Holes3462 and3470 on diagonally opposite sides ofhub3450 are also aligned to allow a bone screw to be inserted through the two holes across the hub, passing through a centerline ofhub3450. Since both of these two screw paths cross the centerline at the same location forming an X-pattern, only one screw may be placed through these two pairs ofholes3460/3468 and3462/3470 in any particular procedure.

A third screw may be inserted through the openproximal end3452 ofhub3450 and out through eitherhole3472 orhole3474. Since these two screw paths also overlap, only one screw may be placed though them at a time.

As can be appreciated fromFIGS. 40A-40E and the description above,exemplary hub3450 is symmetrical about a central plane. Sincehub3450 may receive up to three screws, each in one of two positions, there are a total of eight screw patterns that may be used withhub3450, depending on the situation. Additionally, only one or two screws, or no screws, may be used in a particular procedure, if desired. The positions and orientations of the screw holes ofhub3450 relative to previously describedhub3400 may take better advantage of cortical bone locations in some procedures for better anchoring of bone screws. In particular, a screw passing throughhole pairs3456/3464,3458/3466,3460/3468 or3462/3470 ofhub3450 will have a reduced angle relative to a longitudinal axis of a bone as compared with the screw trajectories of similar screws inhub3400. Similarly, a screw passing through eitherhole3472 or3474 will have a different angle from the same screw inhub3400, which in many cases allows the screw ofhub3450 to hit harder bone. Additionally, screw paths of hole pairs3460/3468 and3462/3470 are closer to the proximal end ofhub3450 than similar screw paths inhub3400, allowing the screws to fixate in harder bone located near the end of a bone. All of the new screw trajectories provided byhub3450 may be used with the in vivo hole forming hubs that will be later described below. The trajectories of hole pairs3456/3464,3458/3466,3460/3468 or3462/3470 also form an angle with a central, longitudinal plane containing the curve of hub3450 (in other words, a plane of symmetry of the hole pairs.) In some embodiments, the hole pairs each form an angle with the plane falling in a range of about 5 to 30 degrees.

FIGS. 41A-41E show another exemplary embodiment of a bonefixation device hub3500.Hub3500 is of similar construction tohubs3400 and3450 described above and includesproximal end3502 anddistal end3504. As seen inFIG. 41C,hub3500 includes slottedholes3506,3508, and3510 through the wall thickness on its concave side. As seen inFIG. 41D,hub3500 also includes slottedholes3512,3514, and3516, andangled hole3518 through the wall thickness on its convex side.Holes3506 and3512 on opposite sides ofhub3500 are aligned to allow a first bone screw to be inserted through the two holes across the hub. Similarly, holes3508 and3514 are aligned to receive a second bone screw, and holes3510 and3516 are aligned to receive a third bone screw.Hole3518 is aligned with the opening in theproximal end3502 ofhub3500 to receive a fourth bone screw.

The slotted configuration of hole pairs3506/3512,3508/3514, and3510/3516 allows a bone screw to be received through each of the pairs in a variety of orientations. This arrangement permits a surgeon the flexibility to place bone screws where most appropriate in a particular procedure. For example, a first bone screw may be placed throughholes3506 and3512 such that it resides in the left, middle, or right portion ofhole3506, as viewed inFIG. 41C. The same screw will have another section that may reside in the left, middle, or right portion ofhole3512. With these various combinations, it can be appreciated that the screw can take one of nine basic orientations throughholes3506 and3512, as well as many other orientations between these nine. In other embodiments, a slightly enlarged round hole may be provided on one side of the hub while a slotted hole on the opposite side forms the other hole of the pair.

In this exemplary embodiment, the width of slottedholes3506,3508,3510,3512,3514, and3516 is 2.0 mm. This provides a pilot hole in which a drill bit or screw tip may engage. Material from a portion of the sides of each hole may be removed when the drill bit forms a larger hole in one location of the slotted hole, and/or when a screw is inserted to form threads through the hole. No drilling or threading may be necessary, such as when the slot width is generally the same as the minor diameter of the screw, and the thickness of the hub walls is generally the same as the screw pitch. The slotted holes may also stretch or deform when receiving the screw. As shown inFIG. 41F, relief slit(s)3520 may be provided adjacent to a slottedhole3506 to allow the slot to more easily expand when receiving ascrew3522. Such slits may be formed by laser cutting, electron beam melting (EBM), electrical discharge machining (EDM), etching, stamping, milling, or other fabrication techniques.

FIGS. 42A-42D show another exemplary embodiment of a bonefixation device hub3500′.Hub3500′ is similar tohub3500 described above, but has slotted holes that are oriented longitudinally rather than transversely.Hub3500′ includesproximal end3502′ anddistal end3504′. As seen inFIG. 42C,hub3500′ includes slottedholes3506′,3508′, and3510′ through the wall thickness on its concave side. As seen inFIG. 42D,hub3500′ also includes slottedholes3512′,3514′, and3516′, andangled hole3518′ through the wall thickness on its convex side.Holes3506′ and3512′ on opposite sides ofhub3500′ are aligned to allow a first bone screw to be inserted through the two holes across the hub. Similarly, holes3508′ and3514′ are aligned to receive a second bone screw, and holes3510′ and3516′ are aligned to receive a third bone screw.Hole3518′ is aligned with the opening in theproximal end3502′ ofhub3500′ to receive a fourth bone screw. Exemplary axis lines3524,3526,3528, and3530 are shown inFIG. 42A to show examples paths for the first, second, third, and fourth screws, respectively.

FIGS. 43A-43E show another exemplary embodiment of a bonefixation device hub3550. As seen inFIG. 43D,hub3550 includes at its proximal end3552 a transversely elongated hole3554. Hole3554 allows ascrew3556 to be located along the central axis, or off-axis in either direction as may be desired for engaging harder bone or securing additional bone fragment(s). This of arrangement of hole3554 may be configured to holdscrew3556 tightly at all angles. This may be accomplished, for example, by using a hole3554 slot width that is equal to or smaller than the minor diameter ofscrew3556. The wall thickness ofhub3550 may fit into the screw threads, providing additional locking ofscrew3556. In other embodiments, the angle of elongated hole3554 may be oriented differently as desired.

Special screws may be used to provide additional locking. As shown inFIG. 43E, screw3558 has a tapered edge3560 below itshead3562. Tapered edge3560 serves to wedge screw3558 into slot3554, securing the screw in place. A screw with an expanding head (not shown) may also be used. With this arrangement, a taper or other expanded section may be created once the screw is in place, thereby locking it in position.

FIGS. 44A-44C show another exemplary embodiment of abone fixation hub3600.Hub3600 is provided with an array ofpilot holes3602 over most of its surface. Eachhole3602 may be 0.015 to 0.020 inches in diameter, for example, and serves as a starting point to allow a drill bit or screw tip to penetrate the wall thickness ofhub3600. This makes in vivo screw hole formation possible, while allowing the hub to remain a rigid structure.Holes3602 may be closely spaced such that a screw or screws may be positioned in vivo virtually anywhere the surgeon desires during each particular procedure. Once the drill bit and/or screw is inserted, thehole3602 becomes enlarged to generally the minor diameter of the screw thread, such as to 2.7 mm in diameter, for example. Screw holes may be formed in this way on both sides ofhub3600 in a continuous operation, allowing screw(s) to be positioned across the hub as previously described.

As shown inFIG. 44C,pilot holes3602 may be placed closer to one another so that multiple perforations are consumed by thescrew diameter3604 when the screw hole is formed. This can make in vivo hole formation even easier. Other hole patterns than those shown inFIGS. 44A-44C may be used.

Holes3602 may be fabricated inhub3600 by laser cutting, electron beam melting (EBM), electrical discharge machining (EDM), etching, stamping, drilling, or other fabrication techniques.

FIGS. 45A and 45B show another exemplary embodiment of abone fixation hub3650.Hub3650 has at least a portion that is fabricated from a mesh structure, forming a plurality of diamond or other shapedapertures3652.Apertures3652 may be configured with dimensions smaller than the major diameter of the threads of the bone screws to be used. Aperture dimensions may even be smaller than the minor thread diameter, such that the apertures are stretched and/or deformed as the screw enters the aperture, thereby providing an increased ability to hold the screws in place. The use of amesh hub3650 may reduce the amount or possibility of debris being formed and released inside the body during in vivo screw hole formation.

Apertures3652 may be fabricated inhub3650 by laser cutting, electron beam melting (EBM), electrical discharge machining (EDM), etching, stamping, drilling, or other fabrication techniques.Apertures3652 may also be fabricated by forming slits in plate or tube stock and expanding the material to form the apertures. Another fabrication technique that may be used is forming wires or bands around a mandrel and then welding, brazing, soldering, pressing, melting, gluing, or otherwise joining the wires or bands to each other at their intersections. Other types of porous structures, either with or without more random aperture locations, may be used as well. Multiple layers of mesh may also be combined.

FIGS. 46A and 46B show another exemplary embodiment of abone fixation hub3700.Hub3700 is provided with a plurality ofthin slots3702 along its length.Slots3702 permit in vivo screw hole formation by acting as long pilot holes for drill bits or bone screws. A bone screw tip may be inserted into one of theslots3702 without pre-drilling. Upon insertion, the slot and surrounding slots will deform to make way for the screw, and will provide circumferential pressure to retain the screw.

Although shown staggered and in the longitudinal direction, in other embodiments (not shown) thin slots may be provided in a transverse or other orientation, and/or in other patterns.Slots3702 may be fabricated inhub3700 by laser cutting, electron beam melting (EBM), electrical discharge machining (EDM), etching, stamping, drilling, or other fabrication techniques.Thin slots3702 may generally require less material removal than other hub embodiments.

FIGS. 47A and 47B show another exemplary embodiment of abone fixation hub3750.Hub3750 comprises three separately formed hubs assembled together: aninner hub3752, a mid-hub3754, and anouter hub3756.Mid-hub3754 has a larger diameter thaninner hub3752 so that mid-hub3754 may be placed overinner hub3752, as illustrated inFIGS. 47A and 47B. Similarly, outer hub756 has a larger diameter than mid-hub3754 so thatouter hub3756 may be placed over mid-hub3754, as also illustrated in the figures. In this embodiment, all threehub components3752,3754, and3756 have the same bend radius and the same arc length. Once assembled, the threehub components3752,3754, and3756 may be retained at one or both ends by other components of the associated bone fixation device, and/or may be welded or otherwise fastened together.

As seen inFIG. 47B,inner hub3752 andouter hub3756 have spirally formedslots3758 and3760, respectively.Slots3758 and3760 may be formed such that they line up when the individual hubs are assembled. Eachhub3752 and3756 may also be provided with an upper spine (3762 and3764, respectively), and a lower spine (not seen inFIG. 47B). The spines are solid regions running the length of the hubs that provide rigidity, and are positioned in areas that do not typically receive screws.Mid-hub3754 has longitudinally extendingslots3766 rather than spiral slots. When the three slot patterns are assembled in a coaxial unit, as shown inFIG. 47A, a hub is formed that may be quite rigid. Pilot holes are formed whereslots3760,3766, and3758 line up radially to facilitate in vivo screw hole formation. When a screw is inserted in such a pilot hole, one or more of the slots may deform to receive the screw.

One, two, three, four, or more hub layers may be used in this manner to form a single layer or composite hub. Other slot patterns and widths may be used as appropriate. Some of the layers may incorporate round or other aperture shapes instead of or in addition to the slots shown in this example.

In many of the hub embodiments described above, one or more screws may be placed into just a single side of the hub, or completely across the hub through both sides.

Referring toFIGS. 48A-48D, a tubular gripper embodiment is shown.Gripper3800 is generally tube-shaped and has a series ofslots3802 formed through its wall thickness along the length and around the circumference of the tube. In this embodiment, eachslot3802 is helical, as shown. In other embodiments, the slots may be straight or form other patterns.Slots3802 may be formed by laser cutting, punching, milling, etching, sawing, electro-discharge machining, or otherwise removing material from the body of the gripper.Slots3802 may also be created by molding, extruding or otherwise forming thebeam members3804 between theslots3802.Gripper3800 may be formed from metal, composite, plastic, amorphous materials, shape memory alloy, and/or other suitable materials.

FIGS. 48A and 48 B show gripper3800 in a retracted state. By applying a compressive axial load to the ends ofgripper3800 as with the previously described grippers,gripper3800 expands radially outward into a deployed state, as shown inFIGS. 48C and 48D. In the deployed state, mid-portions ofbeam members3804 arc outwardly to contact an inner surface of bone to anchor an attached fixation device to the bone. By applying a tensile force to the ends ofgripper3800, it may be at least partially returned to the retracted state. In some embodiments of the invention,beam members3804 undergo only elastic deformation when moving into the deployed state. In other embodiments,members3804 may undergo plastic deformation.

In some embodiments, a bone fixation device incorporating gripper(s)3800 may rotationally constrain the ends of the gripper relative to one another as the ends move axially. In other embodiments, the ends may be left unconstrained. In still other embodiments, the ends ofgripper3800 may be biased or forced to rotate relative to one another as they move axially closer and/or farther apart. Such arrangements may advantageously increase or decrease the amount of expansion that occurs when the gripper is axially compressed, and/or may similarly alter the amount of retraction that occurs when the gripper is axially pulled under tension.

FIGS. 49A and 49B show another tubular gripper embodiment. Gripper3900 is similar togripper3800, butbeam members3904 each have an offsetportion3906 located at their mid-portions. These offsetportions3906 create a pair of sharp points on opposite sides of each beam member that can enhance the gripping effectiveness of gripper3900 by engaging with the interior bone surface when the gripper is deployed.

FIGS. 50A and 50B show another tubular gripper embodiment.Gripper4000 is similar to bothgrippers3800 and3900.Gripper4000 includes a protrudingmember4006 located along each side of eachbeam member4004. Pointed ends of opposite facing protrudingmembers4006 provide additional gripping engagement whengripper4000 is deployed.

FIGS. 51A and 51B show another tubular gripper embodiment.Gripper4100 includes a first series of beam members4104 helically extending from a first end of the gripper, and a second series of opposing beam members4106 helically extending from the opposite end of the gripper and which interdigitate with the first series4104. The first series of beam members4104 are interconnected with the second series4106 by a series of short leaf springs4108 around the mid-circumference ofgripper4100. As gripper4100 axially compresses and beam members4104 and4106 bend toward a deployed state, the distal ends4110 of members4104 and4106 engage with the interior surface of the bone.

FIGS. 52A and 52B show another tubular gripper embodiment. Gripper4200 of this embodiment is similar togripper4100 of the previous embodiment, butfewer beam members4204 and4206 are employed in gripper4200, and thebeam members4204 and4206 are interconnected with longer, Z-shapedleaf springs4208. As gripper4200 axially compresses andbeam members4204 and4206 bend toward a deployed state, the distal ends4210 ofmembers4204 and4206 engage with the interior surface of the bone.

FIGS. 53 A and53B show another tubular gripper embodiment.Gripper4300 of this embodiment is also similar to gripper4100 shown inFIGS. 51A and 51B, but thebeam members4304 and4306 are interconnected with serpentine leaf springs4308. As gripper4300 axially compresses andbeam members4304 and4306 bend toward a deployed state, the distal ends4310 ofmembers4304 and4306 engage with the interior surface of the bone.

In any of the above-described tubular gripper embodiments, a thinned down portion (not shown) may be provided at a predetermined location or locations along one or more of the beam members to cause the beam member to bend at that particular location during deployment under axial compressive loading.

FIGS. 54A-54F show another exemplary embodiment of abone fixation device4400 constructed according to aspects of the present invention.Device4400 includes acurved hub4402, aproximal gripper4404, a flexible-to-rigid body portion4406, adistal gripper4408, and anactuation lead screw4410.FIGS. 54A-54C show device4400 in an undeployed state, whileFIGS. 54D-54F show device4400 in a deployed state.

FIGS. 55A-55G show further details ofdistal gripper4408 ofdevice4400 described above. As seen inFIG. 55G,distal gripper4408 comprises aproximal end piece4450, adistal end piece4452, atubular core4454, afirst gripper arm4456, asecond gripper arm4458, twolink bars4460,4460, twolong pins4462,4462, and twoshort pins4464,4464.

Tubular core4454 may include aflange4466 at its distal end as shown for engaging in acircular bore4468 in the distal side ofdistal end piece4452 for transferring axial loads.Tubular core4454 may be fastened todistal end piece4452, such as by a press fit and/or welding.Proximal end piece4450 includes a central opening for receiving thetubular core4454 such that proximal end piece may freely slide along thetubular core4454.

Upper portions of both first andsecond gripper arms4456,4458 are pivotably connected toproximal link bar4460 by a singlelong pin4462.Proximal link bar4460 in turn is pivotably connected toproximal end piece4450 by ashort pin4464. Similarly, lower portions of both first andsecond gripper arms4456,4458 are pivotably connected todistal link bar4460 by the otherlong pin4462.Distal link bar4460 in turn is pivotably connected todistal end piece4452 by the othershort pin4464.

At least a portion oftubular core4454 may be internally threaded for engaging actuation lead screw4410 (shown inFIGS. 54A-54F). Asactuation lead screw4410 is turned in an actuation or deployment direction,tubular core4454 and attacheddistal end piece4452 is drawn in a proximal direction. Sinceproximal end piece4450 is prevented from also moving in the proximal direction by flexible-to-rigid body portion4406 (shown inFIGS. 54A-54F),tubular core4454 telescopes throughproximal end piece4450 into the central bore of flexible-to-rigid body portion4406. In other words, when gripper4408 is deployed, its distal andproximal end pieces4452,4450 are moved toward each other, withproximal end piece4450 sliding along the outside surface oftubular core4454. As this occurs, first andsecond gripper arms4456,4458 are forced to rotate from a retracted, undeployed position, as shown inFIGS. 55A-55C, toward an extended, deployed position, as shown inFIGS. 55D-55F. In the deployed position, the outward tips ofgripper arms4456,4458 engage with bone tissue within the intramedullary space of the bone to securegripper4408 anddevice4400 within the bone.

If desired,gripper4408 may be moved back to the retracted, undeployed state by turning actuation lead screw4410 (shown inFIGS. 54A-54F) in an opposite direction, causingtubular core4454 and attacheddistal end piece4452 to move in a distal direction, such thattubular core4454 recedes from within flexible-to-rigid body portion4406, distal andproximal end pieces4452,4450 separate, andgripper arms4456,4458 rotate back to the retracted position shown inFIGS. 55A-55C.

According to aspects of the present invention, in some embodiments thetubular core4454 serves to isolate the threads of theactuation lead screw4410 from corners and other geometry that could potentially damage the screw. This can improve reliability of the device and reduce or eliminate the chance of particulate matter being dislodged from the device and migrating into the patient.Tubular core4454 may also serve to protectactuation lead screw4410 from bending moments generated by the gripper during deployment. This in turn makes the device more robust and enables the screw to provide higher torque and higher tension performance.

Referring toFIGS. 56-58, another embodiment of a bone fixation device with a compression screw is shown.Device4500 has aspects that are similar in construction and operation to the previously described bone fixation devices.Device4500 includes aproximal gripper4502, flexible-to-rigid body portion4504, anddistal gripper4506. As can been seen in the figures, flexible-to-rigid portion4504 of the elongate body ofdevice4500 is disposed at a location on the elongate body distal to afirst gripper4502 and proximal to asecond gripper4506.

As shown inFIG. 57, one embodiment of acompression screw device4500 includes two separate actuators. Thefirst actuator4508 is located internally withindevice4500 and operates in similar fashion to the actuators of devices previously described herein.First actuator4508 includes an internally threadedtube4510 that is driven by a keyed feature at its proximal end.Tube4510 is coupled to externally threadedrod4512. Whentube4510 is rotated,rod4512 is drawn in a proximal direction. Ramped surfaces at the distal end ofrod4512 cause bendable arms ofdistal gripper4506 to be outwardly deployed.

In one embodiment, thesecond actuator4514 ofdevice4500 comprises an externally threaded compression screw having a central lumen. The compression screw is coupled to internal threads withinproximal gripper4502. In some embodiments, the compression screw outwardly deploys one, two, three, four or more bendable gripper arms by driving the gripper arms distally against ramped surface(s). In some embodiments, the gripper arm(s) do not move axially when deployed. Instead, the compression screw is moved axially in a proximal direction. In one embodiment, as shown inFIG. 57, the compression screw has a variable diameter, with, for example, a larger diameter than the internal diameter of a portion the proximal gripper, so that movement of the compression screw urges the gripper arms in an outward direction. As shown inFIG. 57, the distal end of the compression screw threading has a greater diameter than the proximal threading or proximal body on the compression screw. In some embodiments,slots4515 may be provided in the proximal end ofdevice4500 to resist torque fromproximal gripper4502.

In operation,device4500, withgrippers4502 and4506 in a retracted state, may be inserted into the intramedullary space within a bone, such as aclavicle bone4516 as shown inFIG. 58. Oncedevice4500 is in place inside the bone, thefirst actuator4508 may be actuated from the proximal end ofdevice4500 by inserting a drive tool through the central lumen of the compression screw of thesecond actuator4514, engaging the distal end of the drive tool with the keyed end oftube4510 and turning, in a manner similar to that previously described. Longitudinal movement ofrod4512 toward the proximal end ofdevice4500 causes flexible-to-rigid body portion4504 to foreshorten and assume its rigid state, and causesdistal gripper4506 to outwardly deploy against the bone, such as themedial segment4518 of theclavicle bone4516 shown inFIG. 58. The drive tool is then removed, and a drive tool having a larger keyed end is inserted into the keyed end of the compression screw to turn thesecond actuator4514, causing the bendable arms ofproximal gripper4502 to outwardly deploy against the bone, such as thelateral segment4520 of theclavicle bone4516.

In another embodiment, thedevice4500 is configured for insertion in to a bone, such as the clavicle bone from a medial to lateral direction. Longitudinal movement ofrod4512 toward the proximal end ofdevice4500 causes flexible-to-rigid body portion4504 to foreshorten and assume its rigid state, and causesdistal gripper4506 to outwardly deploy against the bone, such as thelateral segment4520 of theclavicle bone4516. The drive tool is then removed, and a drive tool having a larger keyed end is inserted into the keyed end of the compression screw to turn thesecond actuator4514, causing the bendable arms ofproximal gripper4502 to outwardly deploy against the bone, such as themedial segment4518 of theclavicle bone4516.

In some embodiments, any of the devices for insertion into a bone for fracture fixation of a clavicle can be inserted using a medial approach. In some instances, a medial approach can be advantageous for use on fractures, taking advantage of the clavicle's S-shape curvature. For example, a medial approach can be used on the medial half of the middle third of the bone. In some embodiments, a medial approach can also be advantageous for use in small clavicles. In one embodiment, a makes it possible to flip embodiments of the procedures from a lateral to medial approach to a medial to lateral approach. In one embodiment, the medial prep becomes lateral prep and vice versa. In one embodiment, a medial exit point can be formed approximately 1-2 cm lateral to sternal end, slightly inferior, lateral to SC joint. In one embodiment, the exit point can be approximately tangent to the natural curvature of the medial side. In one embodiment, a medial approach for a medial midshaft fracture using a rapid preparation technique can include any of the following steps: a medial exit with K-Wire from fracture site, preparation of a medial fragment with a 4.5 mm drill, reduction of the fracture, driving a spade wire into the lateral fragment, reaming over a spade wire, measuring with a reamer depth gauge, insertion of the appropriate device or implant, actuation of the implant, and insertion of a cross screw or a compression screw.

In one embodiment, as shown inFIGS. 59-65, acompression screw device4500 includes one or more actuators. In one embodiment, there are two actuators. Thefirst actuator4508 is located internally withindevice4500 and operates in similar fashion to the actuators of devices previously described herein. In one embodiment

In one embodiment, thefirst actuator4508 includes a threadedrod4512. In one embodiment, thefirst actuator4508 has apilot wire4509 extending proximally and configured for slideably guiding or directing tools or components to thedevice4500 from the proximal direction. If apilot wire4509 embodiment is used, the tools and/or components advanced along thepilot wire4509 can include a pilot wire lumen.

In one embodiment, thefirst actuator4508 has a keyed feature at its proximal end, such that the threadedrod4512 can be directly driven or rotated by the first actuator tool. In one embodiment, the body of thedevice4500 is internally threaded and configured to be coupled to the threadedrod4512.

In another embodiment, thefirst actuator4508 includes a threadedtube4510 that is driven by akeyed feature4511 at its proximal end by the first actuator tool. The threadedtube4510 can rotate with respect to the body of thedevice4500. In one embodiment, the first actuator tool includes a pilot wire lumen for sliding over thepilot wire4509 to access thekeyed feature4511. The threadedtube4510 is coupled to the threadedrod4512. Whentube4510 is rotated in a first direction, therod4512 is drawn in a proximal direction. Ramped surfaces at the distal end ofrod4512 cause bendable arms ofdistal gripper4506 to be outwardly deployed, as shown inFIGS. 59 to 60, andFIGS. 62 to 64.

In one embodiment, thesecond actuator4514 ofdevice4500 comprises an externally threaded compression screw having acentral lumen4517. The compression screw is coupled to internal threads withinproximal gripper4502. In some embodiments, the compression screw outwardly deploys one, two, three, four or more bendable gripper arms by driving the gripper arms distally against ramped or sloped surface(s). In some embodiments, the gripper arm(s) do not move axially when deployed. In some embodiments,slots4515 may be provided in the proximal end ofdevice4500 to resist torque fromproximal gripper4502. In various embodiments, adevice4500 can be inserted in a lateral to medial direction. In some embodiments, a device can be inserted in a medial to lateral direction.

In various embodiments, a surgical technique for deploying and/or removing adevice4500 can include any of the following steps.

In one embodiment, a pre-operative evaluation can comprise using AP and 45-degree cephalic tilt fluoroscopic views to evaluate the location of a clavicle fracture and associated fragments. Confirm that clear fluoroscopic images of the entire length of the clavicle can be obtained. Determine if a minimum depth of 50 mm can be achieved in the intramedullary canal of medial segment from the most medial edge of the fracture.

In one embodiment, preparation and patient positioning can involve positioning the patient in a modified beach chair position and utilizing an Allen table to gain access to posterior shoulder on the fractured side. A C-Arm can be brought in from across the body or over the top of the table. Support of the arm on the fractured side can be provided by the use of an adjustable armrest. Expose and prep the entire aspect of the clavicle from medial to lateral, including the AC joint and posterior shoulder. Alternatively, the orientation of the clavicle relative to the C-Arm can be changed by flexion or extension of the arm.

In one embodiment, surgical exposure includes making a 3 cm length horizontal or oblique incision directly over the fracture site and bluntly dissect the soft tissue structures to expose the fracture. Remove callus/scar tissue sufficiently to start medial and lateral preparation. Ensure uponreduction 50% bony apposition of the medial and lateral segments is possible.

In one embodiment, preparation of the medial segment involves elevating the medial fracture segment and secure with a bone reduction clamp. Identify the intramedullary canal with fluoroscopic guidance and use the 2 mm drill to establish a starter hole (approximately 20 mm in depth). Follow with the 3.5 mm drill or 3 mm straight trocar to increase the diameter of the starter hole. Under fluoroscopic guidance, introduce and advance a 3 mm curved trocar, followed by a 4.5 mm curved cutting awl into the medial canal, using +/−15-degree rotating hand motions until a minimum 50 mm depth is achieved. Confirm that the curve of the awl is aligned with the curvature of the clavicle.

In one embodiment, preparation of the lateral segment includes elevating the lateral fracture segment and securing it with a bone reduction clamp. The arm can be externally rotated to help access the lateral canal. Identify the intramedullary canal with fluoroscopic guidance and use the 2 mm drill to establish a starter hole to a depth of approximately 20 mm. Introduce and advance a 4.5 mm aimer awl until the awl is fully seated in the canal but has not breached the cortex. Drive a 1.6 mm K-Wire through the cannulated aimer awl under fluoroscopic guidance to exit the clavicle bone posterior lateral to the Conoid Tubercle. When viewed in the AP view, a lateral exit point in the lateral fragment is at the equator of the posterior clavicle halfway between the Conoid Tubercle and the AC Joint. Tent the skin and make a small incision over the palpable K-Wire tip to expose the exit point. Remove the aimer awl while retaining the K-Wire. Place a 4.5 mm cannulated drill bit over the K-Wire and drill a channel through the lateral segment from lateral to medial. Remove the K-Wire and leave the drill bit in place to act as a guide.

In one embodiment, fracture reduction and canal preparation can include loading the spade tip guide wire through the 4.5 mm drill bit with a spade tip directed toward the medial segment. Reduce the fracture and introduce the guide wire into the medial segment until a marker, such as a lateral gold band, on the guide wire is within the lateral end of the 4.5 mm drill bit. Remove the drill bit while retaining the guide wire. Ensure the fracture is reduced over the guide wire. Place the flexible reamer over the guide wire and under fluoro, ream from lateral to medial.

In one embodiment, a rapid preparation may be used to prepare the medial segment without using the awls. With the medial pilot hole established and the lateral segment prepared, the spade tip guide wire can be driven through the 4.5 mm drill bit into the medial segment under power. Drive the wire into the medial segment until a marker (e.g., such as a gold band) on the wire is within the lateral end of the drill. Remove the drill taking care to retain the placement of the wire. Verify the position of the wire using fluoroscopy. Use the flexible reamer to ream from lateral to medial to the tip of the spade wire.

In one embodiment, implant sizing and preparation can involve placing a reamer depth gauge over the reamer and advancing it until it contacts the lateral bone. Measure the length off of the scale. Determine the appropriate implant length by subtracting 10 mm off of the measured length to account for countersinkingDevices4500 can be available in 90, 100, 110, and 120 mm lengths. Remove the depth gauge but retain the guide wire. Use the 5 mm cannulated countersink drill to create a 10 mm deep countersink at the lateral entry. The drill has a step-off at 10 mm to limit the countersink depth. Prepare thedevice4500 by aligning the notches in the hub and hub attachment tube and tightening the hub attachment screw.

In one embodiment, implant insertion and fixation involves inserting the actuation driver into the hub of thedevice4500. Load a soft tissue trocar and U-shaped guide assembly through the posterior soft tissue and into the entry hole in the lateral clavicle bone. Retain the position of the U-shaped guide and remove the soft tissue trocar. In one embodiment, an optional step can be used if difficulty is encountered during implant insertion. The insertion guide can be introduced from the fracture through the lateral segment to help guide thedevice4500 into the entry hole. In an embodiment, with the fracture adequately reduced, fully advance thedevice4500 through the U-shaped guide into the entry hole and across the fracture. Countersink thedevice4500 10 mm below the lateral entry point. Confirm positioning with fluoroscopic visualization. Position thedevice4500 such that the posterior indicator pin is directed posteriorly and parallel with the top of the shoulder. This will ensure that thedevice4500 is oriented correctly. Expand the grippers by turning the actuation driver in a first (e.g., clockwise or counterclockwise) direction, until markers (e.g., white lines) on the knob are collinear or match. Confirm satisfactory fixation of thedevice4500 to the clavicle by gently pulling on the implant assembly and confirming position with fluoroscopic visualization.

In one embodiment, compression screw placement involves removing the actuation driver, hub attachment tube, and hub attachment screw from thedevice4500. Insert the compression screw over the pilot wire extending from thedevice4500. Use the 2.5 mm cannulated screw driver to tighten the compression screw until the fracture is adequately compressed. Confirm reduction under fluoroscopic visualization. Use the 2.0 mm drill bit to drill down to the edge of the anterior cortex. 4. Bend the pilot wire over approximately an inch from the end. Rotate the wire to remove.

In one embodiment, final evaluation and closure includes evaluating appropriate fixation of thedevice4500 and deployment of the grippers in both AP and 45° cephalic radiographic views. Conclude the procedure with appropriate soft tissue and incision closure.

In one embodiment, post-operative care includes fitting the patient with a sling or shoulder immobilizer. Patients should avoid repetitive forward flexion or abduction past 90-degrees and have repeat x-rays at 2, 6 and 12-weeks or until healed. Once there is evidence of healing (callus formation bridging the fracture), the patient may increase activities.

In one embodiment,device4500 removal from a bone is generally not considered less than 12-16 weeks after surgery and generally after radiographic healing can be verified. In some embodiments, it may be advantageous to remove thedevice4500 from highly active individuals after radiographic healing has been verified.

Referring toFIGS. 66-68, another embodiment of a bone fixation device is shown.Device4600 is similar in construction and operation to the previously described bone fixation devices.Device4600 includes aproximal gripper4602, flexible-to-rigid body portion4604, anddistal gripper4606. As can been seen in the figures, flexible-to-rigid portion4604 of the elongate body ofdevice4600 is disposed at a location on the elongate body distal to afirst gripper4602 and proximal to asecond gripper4606. In this embodiment, the bendable arms ofproximal gripper4602 are spaced 420 degrees apart around the axis of the device.

Device4600 includes acurved hub4608 having astraight section4610 for holdinginner actuation mechanism4612. In this embodiment, thesingle actuation mechanism4612 actuates bothgrippers4602 and4606. Flexible-to-rigid portion4604 includes an interlocking cut pattern that prevents uncoiling of the body under tension. The body also has an anti-rotation feature built into it. Achamfer4614 is provided at the proximal end of flexible-to-rigid portion4604 to cause the bendable arms ofproximal gripper4602 to expand outwardly whenbody portion4604 is driven proximally. Thedistal portion4615 ofcurved hub4608 maybe tapered as shown to allow for easier implantation intraoperatively.

FIG. 68 illustrates howdevice4600 may be used with anexternal fixture4616 to allow screw holes to be formed inhub4608 or flexible-to-rigid portion4604 in vivo. In some embodiments,device4600 is devoid of any preformed screw holes before it is installed in the bone. In some embodiments,hub4608 is made from a biocompatible material such as PEEK to allow the screw holes to be easily formed in vivo. Adepth gage4618 may be provided on thescrew forming tool4620 to aid in screw hole formation.

Referring toFIGS. 69-70, another embodiment of a bone fixation device is shown.Device4700 is similar in construction and operation to the previously described bone fixation devices.Device4700 includes acurved hub4702 at its proximal end, a flexible-to-rigid body portion4704, and asingle gripper4706 located at its distal end. As can been seen in the figures, the single actuatablebone engaging gripper4706 is disposed on the elongate body at a location distal to the flexible-to-rigid portion4704 of the elongate body ofdevice4700.

Referring toFIGS. 71-74, another embodiment of a bone fixation device is shown.Device4800 is similar in construction and operation to the previously described bone fixation devices.Device4800 includes aproximal gripper4802, flexible-to-rigid body portion4804, anddistal gripper4806. As can been seen in the figures, flexible-to-rigid portion4804 of the elongate body ofdevice4800 is disposed at a location on the elongate body distal to afirst gripper4802 and proximal to asecond gripper4806. In this embodiment, each of thegrippers4802 and4806 includes four fan-likebendable arms4810 similar to those previously described.

FIGS. 72 and 73 show cross-sections ofdevice4800, in which theactuator4812 can be seen. The distal end ofactuator rod4812 is provided with acam surface4814 for outwardly deployingbendable arms4810 ofdistal gripper4806 from the retracted position shown inFIG. 72 to the deployed position shown inFIG. 73.FIG. 74shows device4800 implanted inclavicle bone4816 acrossfracture4818. One ormore screws4820 may be used to secure the proximal end ofdevice4800, as previously described.

Referring toFIGS. 75-78, another embodiment of a bone fixation device is shown.Device4900 is similar in construction and operation to the previously described bone fixation devices.Device4900 includes astraight hub4902 at its proximal end, flexible-to-rigid body portion4904, anddistal gripper4906. As can been seen in the figures, the single actuatablebone engaging gripper4906 is disposed on the elongate body at a location distal to the flexible-to-rigid portion4904 of the elongate body ofdevice4900. In this embodiment,single gripper4906 includes four fan-likebendable arms4910 similar to those previously described.

FIGS. 76 and 77 show cross-sections ofdevice4900, in which the actuator4912 can be seen. The distal end of actuator rod4912 is provided with acam surface4914 for outwardly deployingbendable arms4910 ofdistal gripper4906 from the refracted position shown inFIG. 76 to the deployed position shown inFIG. 77.FIG. 78shows device4900 implanted inclavicle bone4916 acrossfracture4918. One ormore screws4920 may be used to secure the proximal end ofdevice4900, as previously described.

In various embodiments, a surgical technique for deploying and/or removing any of the implants or devices, such as (but not limited to)devices100,3100,3200,3300,3400,3500,4400,4500,4600,4700,4800,4900 and other devices, can include any of the following steps.

In one embodiment, a pre-operative evaluation can comprise using AP and 45-degree cephalic tilt fluoroscopic views to evaluate the location of a clavicle fracture and associated fragments. Confirm that clear fluoroscopic images of the entire length of the clavicle can be obtained. Determine if a minimum depth of 50 mm can be achieved in the intramedullary canal of medial segment from the most medial edge of the fracture.

In one embodiment, preparation and patient positioning can involve positioning the patient in a modified beach chair position and utilizing an Allen table to gain access to posterior shoulder on the fractured side. A C-Arm can be brought in from across the body or over the top of the table. Support of the arm on the fractured side can be provided by the use of an adjustable armrest. Expose and prep the entire aspect of the clavicle from medial to lateral, including the AC joint and posterior shoulder. Alternatively, the orientation of the clavicle relative to the C-Arm can be changed by flexion or extension of the arm.

In one embodiment, surgical exposure includes making a 3 cm length horizontal or oblique incision directly over the fracture site and bluntly dissect the soft tissue structures to expose the fracture. Remove callus/scar tissue sufficiently to start medial and lateral preparation.

In one embodiment, preparation of the medial segment involves elevating the medial fracture segment and secure with a bone reduction clamp. Identify the intramedullary canal with fluoroscopic guidance and use the 2 mm drill to establish a starter hole (approximately 20 mm in depth). Follow with the 3.5 mm drill or 3 mm straight trocar to increase the diameter of the starter hole. Under fluoroscopic guidance, introduce and advance a 3 mm curved trocar, followed by a 4.5 mm curved cutting awl into the medial canal, using +/−15-degree rotating hand motions until a minimum 50 mm depth is achieved. Confirm that the curve of the awl is aligned with the curvature of the clavicle.

In one embodiment, preparation of the lateral segment includes elevating the lateral fracture segment and securing it with a bone reduction clamp. The arm can be externally rotated to help access the lateral canal. Identify the intramedullary canal with fluoroscopic guidance and use the 2 mm drill to establish a starter hole to a depth of approximately 20 mm. Introduce and advance a 4.5 mm aimer awl until the awl is fully seated in the canal but has not breached the cortex. Drive a 1.6 mm K-Wire through the cannulated aimer awl under fluoroscopic guidance to exit the clavicle bone posterior lateral to the Conoid Tubercle. When viewed in the AP view, a lateral exit point in the lateral fragment is at the equator of the posterior clavicle halfway between the Conoid Tubercle and the AC Joint. Tent the skin and make a small incision over the palpable K-Wire tip to expose the exit point. Remove the aimer awl while retaining the K-Wire. Place a 4.5 mm cannulated drill bit over the K-Wire and drill a channel through the lateral segment from lateral to medial. Remove the K-Wire and leave the drill bit in place to act as a guide.

In one embodiment, fracture reduction and canal preparation can include loading the spade tip guide wire through the 4.5 mm drill bit with a spade tip directed toward the medial segment. Reduce the fracture and introduce the guide wire into the medial segment until a marker, such as a lateral gold band, on the guide wire is within the lateral end of the 4.5 mm drill bit. Remove the drill bit while retaining the guide wire. Ensure the fracture is reduced over the guide wire. Place the flexible reamer over the guide wire and under fluoro, ream from lateral to medial.

In one embodiment, a rapid preparation may be used to prepare the medial segment without using the awls. With the medial pilot hole established and the lateral segment prepared, the spade tip guide wire can be driven through the 4.5 mm drill bit into the medial segment under power. Drive the wire into the medial segment until a marker (e.g., such as a gold band) on the wire is within the lateral end of the drill. Remove the drill taking care to retain the placement of the wire. Verify the position of the wire using fluoroscopy. Use the flexible reamer to ream from lateral to medial to the tip of the spade wire.

In one embodiment, implant sizing and preparation can involve placing a reamer depth gauge over the reamer and advancing it until it contacts the lateral bone. Determine the appropriate length implant by reading the length on the scale. In various embodiments, implants are available in 90, 100, 110, 120, and 130 mm lengths. If an implant measurement falls between two sizes, choose the longer implant. Remove depth gauge, guide wire, and reamer. Prepare the implant by inserting the hub attachment tube into the outrigger and aligning markings, (such as, e.g., an “A” to an “A” letter marking). Insert the attachment screw into the hub of the implant. Align the notches in the hub and hand tighten.

In one embodiment, implant insertion and fixation can include inserting the actuation driver into the hub of the implant. Load the soft tissue trocar and U-shaped guide assembly through the posterior soft tissue and into the entry hole in the lateral clavicle bone. Retain the position of the U-shaped guide and remove the soft tissue trocar. In one embodiment, an optional step can be used if difficulty is encountered during implant insertion: the insertion guide can be introduced from the fracture through the lateral segment to help guide the implant into the entry hole. In an embodiment, with the fracture adequately reduced, fully advance the implant through the U-shaped guide into the entry hole and across the fracture. Confirm positioning with fluoroscopic visualization. Position the outrigger in a parallel plane with the top of the shoulder, so that the direction of the screw will engage the cortex of the lateral clavicle bone. Expand the grippers by turning the actuation driver in a clockwise direction, until the white lines on the knob are collinear. Confirm satisfactory fixation of the implant to the clavicle by gently pulling on the outrigger assembly and confirming position with fluoroscopic visualization.

In one embodiment, lateral screw placement involves removing the actuation driver from the outrigger. Insert the soft tissue trocar into the external sheath. Make a small stab incision and advance the sheath and trocar until it comes in direct contact with the clavicle bone. Remove the soft tissue trocar and insert the drill guide into the external sheath. Under fluoroscopic guidance, use a 2.0 mm drill bit to drill down to the edge of the anterior cortex. Use the scale on the drill guide to measure the appropriate length 2.7 mm screw. Subtract 2 mm to allow for screw countersinking. Remove the drill guide from the external sheath and insert the screw guide. Insert the screw and tighten with a 2.5 mm hex driver. Verify that the screw has passed through the implant by reinserting the actuation driver.

In one embodiment, final evaluation and closure includes evaluating appropriate fixation of the implant and deployment of the grippers in both AP and 45° cephalic radiographic views. Cerclage techniques can be used when butterfly fragments are present and/or to provide additional compressive fixation when a significant degree of obliquity is encountered in the fracture pattern. The notched Crego elevator may be used as a guide to pass the suture needle around the clavicle. A #1 PDS suture on a CTX needle can also be used. Conclude the procedure with appropriate soft tissue and incision closure.

In one embodiment, post-operative care includes fitting the patient with a sling or shoulder immobilizer. Patients should avoid repetitive forward flexion or abduction past 90-degrees and have repeat x-rays at 2, 6 and 12-weeks or until healed. Once there is evidence of healing (callus formation bridging the fracture), the patient may increase activities.

In one embodiment, device removal from a bone is generally not considered less than 12-16 weeks after surgery and generally after radiographic healing can be verified. In some embodiments, it may be advantageous to remove the device from highly active individuals after radiographic healing has been verified.

Referring toFIGS. 79 and 80, another embodiment of a flexible-to-rigid body portion5000 is shown.FIG. 79 shows a perspective view ofbody portion5000 having a spiral cut formed through its tube wall.FIG. 80 shows a plan view of the cut pattern laid flat. Under axial compression, the extensions formed by the spiral cut collide, aiding in the rigidity of the construct.

Referring toFIGS. 81 and 82A, another embodiment of a flexible-to-rigid body portion5100 is shown.FIG. 81 shows a perspective view ofbody portion5100 having a spiral cut formed through its tube wall.FIG. 82A shows a plan view of the cut pattern laid flat. Axial compression causes the proximally and distally extending features to translate transverse to the longitudinal axis of thebody portion5100. This lateral movement causes keying features formed on the extending features to inter-engage, aiding in the rigidity of the construct.

Referring toFIG. 82B, another embodiment of a flexible-to-rigid body portion5102 is shown in plan view, with the cut pattern laid flat. Like the pattern shown inFIG. 82A, axial compression causes the proximally and distally extending features to translate transverse to the longitudinal axis of thebody portion5102. This lateral movement causes keying features formed on the extending features to inter-engage, aiding in the rigidity of the construct.

Referring toFIGS. 83 and 84, another embodiment of a flexible-to-rigid body portion5200 is shown.FIG. 83 shows a perspective view ofbody portion5200 having a spiral cut formed through its tube wall.FIG. 84 shows a plan view of the cut pattern laid flat. The interlocking features of the spiral cut are transverse to the longitudinal axis of thebody portion5200. This maximizes contact surface in compression to aid in rigidity. The gap between the arms may be varied as shown to increase flexibility in one plane.

Referring toFIGS. 85 and 86, another embodiment of a flexible-to-rigid body portion5300 is shown.FIG. 85 shows a perspective view ofbody portion5300 having a spiral cut formed through its tube wall.FIG. 86 shows a plan view of the cut pattern laid flat. The features of the spiral cut step horizontally, transverse to the longitudinal axis of thebody portion5200. This maximizes contact surface in compression. Varying gaps allow the body to twist more.

Referring toFIGS. 87 and 88, another embodiment of a flexible-to-rigid body portion5400 is shown.FIG. 87 shows a perspective view ofbody portion5400 having a spiral cut formed through its tube wall.FIG. 88 shows a plan view of the cut pattern laid flat. The pattern of the spiral cut includes a sinusoidal wave interrupted by locking features. The gap formed by the cut can be varied longitudinally. For example, the gap atlocations5402,5404 and5406 can get progressively smaller as shown. Whenbody portion5400 is axially compressed, it forms a curve in each segment in which the gap is varied. The resulting shape is a curve which spirals down the length of the body, similar to the shape of a cork screw. In some embodiments, this shape aids the device in being able to grip the interior surfaces of the bone.

FIGS. 89-93 show further details of another exemplaryrotary driver tool6132′, similar to thedriver tool6132 shown inFIG. 32, constructed according to aspects of the invention.Driver tool6132′ maybe used to actuate gripper6108 and compress a flexible-to-rigid body portion afterdevice100 is inserted into bone6106.Driver6132′ may also be used to allow body portion to decompress and gripper6108 to retract if removal ofdevice100 from bone6106 is desired. In the embodiment shown inFIGS. 89-93,driver6132′ includescap110, retainingring112,knob6154′,spring6156,hub6158′, andshaft6162. The distal end ofshaft6162 is provided with amating tip6164, such as one having an Allen, Torx®, Philips, or similar shape, for engaging with keyed socket6130 ofdevice100, such that turningdriver shaft6162 turns actuator6126, as previously described.

The proximal end ofshaft6162 maybe integrally formed withhub6158′, such as with an insert mold process. In this embodiment,knob6154′ is rotatably mounted overhub6158′ such thatknob6154′ can rotate independently fromhub6158′ andshaft6162.Knob6154′ may be restrained from axial movement in the proximal direction (i.e. away from shaft6162) by retainingring112. In this embodiment, retainingring112 engages withgroove114 in the proximal end ofhub6158′, shown inFIG. 93. Atorsion spring6156 may be used tocouple knob6154′ tohub6158′ as shown. More specifically,distal leg116 ofspring6156 engages withslot118 inhub6158′, andproximal leg6120 engages with a similar feature (not shown) withinknob6154′.

With the indirect coupling arrangement just described, asknob6154′ is rotated abouthub6158′ andshaft6162,spring6156 urgeshub6158′ andshaft6162 to rotate in the same direction. Rotational resistance applied bydevice100 toshaft tip6164 will increase in this embodiment as gripper6108 engages bone6106, and flexible-to-rigid body portion compresses. As more torque is applied toknob6154′, it will advance rotationally with respect tohub6158′ astorsion spring6156 undergoes more stress.

A pair ofmarks122 may be provided onknob6154′ for aligning with a corresponding pair ofmarks124 onhub6158′ when a predetermined torque is applied toknob6154′. In this manner, a surgeon can usedriver6132′ to apply an exact amount of torque todevice100. This can help ensure that gripper6108 is adequately set in bone6106, body portion is sufficiently compressed, and excessive torque is not being applied that might damagedevice100, bone6106 or cause slippage therebetween.

Driver6132′ may be calibrated by not applyingmarks122 toknob6154′ until after the driver is fabricated, assembled and calibrated.Marks124 may be molded onto the distal surface ofhub6158′ as shown during fabrication. Aftertool6132′ is assembled, eithertool tip6164 orknob6154′ can be held in a stationary position while a predetermined torque is applied to the other component, such as with a precisely calibrated torque wrench. With this known torque applied,knob6154′ will have moved rotationally relative tohub6158′ from its relaxed position. Once in this moved position, marks122 maybe applied toknob6154′ directly adjacent tomarks124 onhub6158′. When the predetermined torque is released, marks122 and124 will rotationally separate asknob6154′ returns to its relaxed position, as shown inFIG. 89. During use, the user merely needs to alignmarks122 withmarks124 to obtain the precise torque desired.Marks122 can be applied during calibration by laser etching, mechanical engraving, painting, adhering a marker, melting a portion ofknob6154′, or other such means. Alternatively, other methods ofcalibrating driver6132′ known to those skilled in the art maybe used.

Tool shaft6162 may be configured to be rigid for simplicity and low cost. Alternatively,shaft6162 may be configured to be flexible so that it may access devices implanted in curved intramedullary spaces. This may be accomplished by constructingshaft6162 from a flexible material. However, it many circumstances, it desirable thattool shaft6162 only be flexible in a lateral bending direction, but as stiff as possible in tension, compression and torsion so that the tool is responsive during use. These goals may be accomplished by constructingshaft6162 from one or more layers of oppositely wound wire cable, or by using other composite assembly techniques or materials.

Driver tools6132 and6132′ described above provide ease of torque control for the user to limit the torque of device deployment. The tools increase resolution and reaction time for ceasing application of torque. These tools accurately control the tension on the implanted devices and the load on the bone when deployed, and increase patient safety. Because the tools are designed to be simple, they are inexpensive to manufacture. The tools may be designed and constructed to be sterilized for multiple uses, or they may be optimized for disposable, single-use.

Referring toFIG. 94, a variation of the combination tool ofFIG. 31 will now be described.Combination tool6200 includes abody6202, adevice attachment portion6204, and anapproximating driver6206. Since these components are similar in construction and operation to those on tool6138 described above, they will not be further described.

Combination tool6200 also includes ascrew alignment portion6208, similar to that of tool6138. In this embodiment,tool6200 has a distal bore oraperture6210 and a proximal bore oraperture6212. Each of theapertures6210 and6212 is sized to receive analignment sleeve6214. In some embodiments, eachaperture6210 and6212 has itsown alignment sleeve6214. In other embodiments, asingle alignment sleeve6214 may be alternately placed in one of the twoapertures6210 and6212 at any given time. Retaining sleeve(s)6214 maybe provided with anenlarged head6216 on its proximal end to abut againsttool body6202 when inserted throughapertures6210 and6212. A retaining device such as aknurled thumb screw6218 may be used to thread throughholes6220 intool body6202 to securealignment sleeve6214 withinapertures6210 and6212. In the exemplary embodiment ofFIG. 94, adrill bushing6222 and ascrew bushing6224 are provided, each to be alternately received within the central axial bore ofalignment sleeve6214.Drill bushing6222 has anaxial bore6226 for receiving a drill bit used to drill screw holes in the bone for securing the bone fixation device, as described above.Screw bushing6224 is configured with anaxial bore6228 for receiving a bone screw and the shaft of a screw driver.Barbed fingers6230 longitudinally extending from the distal end ofscrew bushing6224 help retain the screw while it is being driven into the bone with the screw driver.Fingers6230 may flex radially outward when holding a screw, and may flex further outward when releasing the screw.Cutouts6232 may be provided through the distal end ofalignment sleeve6214 to allowfingers6230 ofscrew bushing6224 to flex outward. In this embodiment, flats6234 are provided on the proximal head ofscrew bushing6224 to engage with keyway6236 onalignment sleeve head6216 to properly alignscrew bushing fingers6230 withalignment sleeve cutouts6232. Referring toFIG. 95, an alternative embodiment ofbone fixation device6300 is shown.

Device6300 is similar in construction and operation todevice100 described above.Device6300 also includes a flexible-to-rigid body portion6302 having a generallyhelical slit6304 formed through the tube wall of that portion of the body. Thehelical slit6304 of this embodiment forms a T-shaped pattern such that the body portion adjacent to one side ofslit6304 interlocks with the body portion on the directly opposite side ofslit6304. The interlocking nature of this helical pattern allowsdevice6300 to have only limited axial movement when subjected to axial tension loads. Axial tension loads may occur when a surgeon removesdevice6300 from the intramedullary space within a bone by pulling on the proximal end ofdevice6300. In some embodiments,device6300 can withstand axial tension loads of up to 200 pounds or more. In some embodiments,device6300 has an outside diameter of about 5 mm and a length of about 100 mm.

Referring toFIGS. 96A-96C, another embodiment ofbone fixation device6400 is shown.Device6400 is similar todevice6300 described above, but has a longer flexible-to-rigid body portion. In one embodiment,devices100 and6300 are used with fractures of the proximal ulna. In some embodiments,device100 or6300 may be inserted into the intramedullary space of the proximal ulna through the olecranon. Exemplary indications fordevice6400 include mid-shaft fractures of the ulna. In some embodiments,device6400 has an outside diameter of 4 mm and a length of 200 mm. In other embodiments,device6400 has an outside diameter of 5 mm and a length of 250 mm. Other sizes may be utilized to suit particular anatomies and injury or disease states. Other helical slit patterns on flexible-to-rigid body portions, different gripper locations, gripper types, and a different numbers of grippers (including no grippers) may also be utilized.

It is also envisioned in an alternate embodiment that a tension band in a figure-of-eight or other pattern be used to secure the entry point of the device to a position towards the hand. The tools described herein would provide for drilling one or more holes through the bone and/or the fixation device, and positioning either suture, wire, or other material so that a figure-of-eight or other pattern could be laced along the bone, through a hole in bone. In one embodiment, an elbow can be treated, with lacing along a bone, through a distal hole (toward the hand) of the shaft of the ulna and around the orifice at the proximal (elbow) end of the device. In one embodiment, one or more tension bands can be used.

FIGS. 97,98A and98B show various exemplary embodiments of anatomy or shape conforming body portions constructed according to aspects of the present invention. These and other body portions may be used in bone fixation devices similar to those described above. These body portions may be used in place ofbody portion7114 previously described to allow the device to take on a shape that conforms to a particular anatomy when the body of the device is axially compressed when making the device substantially rigid.

Referring first toFIG. 97, flexible-to-rigidtubular body portion7114′ includes afirst side7410 which forms a solid spine and asecond side7412 which has a series of straight, V-shapedcuts7414 in it. In this embodiment, the V-shapedcuts7414 extend a substantial portion of the way across the diameter oftubular body portion7114′. Asbody portion7114′ is axially compressed in manner similar tobody portion7114 previously described, thefirst side7410 retains its original length because it is solid. Thesecond side7412, however, is foreshortened as V-shapedcuts7414 begin to close. With this difference in lengths betweensides7410 and7412,body portion7114′ takes on a curved shape, withfirst side7410 becoming convex andsecond side7412 becoming concave. The curved configuration ofbody portion7114′ can be designed to match the curve of an intramedullary bone cavity where thebody portion7114′ is being implanted.

FIG. 98A shows another embodiment of a flexible-to-rigidtubular body portion7114″.Body portion7114″ has afirst side7510, asecond side7512, and a series ofwavy slits7514.Slits7514 may be individual slits extending partially around the circumference ofbody portion7114″, leaving a solid spine nearfirst side7510, similar tofirst side7410 shown inFIG. 97. Alternatively, slits7514 may extend completely around the circumference ofbody portion7114′, creating a series of solid wavy rings therebetween. In yet another alternative, slits7514 may extend completely around the circumference ofbody portion7114″ in spiral fashion to create one continuous helical slit.

As can be seen inFIG. 98A, slits7514 have a varying width that increases as they extend fromfirst side7510 tosecond side7512. With this configuration,second side7512 will foreshorten more thanfirst side7510 asslits7514 close during axial compression. This results inbody portion7114″ taking on a curved shape, withfirst side7510 becoming convex andsecond side7512 becoming concave. The alternating curves ofslits7514 provide increased torsional rigidity, particularly whenbody portion7114″ is axially compressed.

FIG. 98B shows yet another embodiment of a flexible-to-rigidtubular body portion7114″′.Body portion7114″′ has afirst side7610, a second side7612, and a series ofwavy slits7614.First side7610 forms a solid spine that does not axially compress. In this embodiment, slits7614 have a generally uniform width. During axial compression,body portion7114″′ takes on a curved shape, withfirst side7610 becoming convex and second side7612 becoming concave.

Alternative designs (not shown), such as wave patterns of an interdigitating saw tooth or square wave, and the like, are also contemplated for increased torsional rigidity. As described above, these patterns may form discrete rings aroundbody portion7114, or these patterns may be superimposed on a helical curve to form a continuous spiral pattern.

FIGS. 99A-99J show further exemplary embodiments of anatomy or shape conforming body portions constructed according to aspects of the present invention. Similar to the body portions described above, the body portions shown inFIGS. 99A-99J may be used in place ofbody portion7114 previously described to allow an implantable bone fixation device to take on a shape that conforms to a particular anatomy when the body of the device is axially compressed when making the device substantially rigid. The body portions shown inFIGS. 99A-99J have interlocking appendages or features that allow each body portion to transform from a generally flexible state to a generally rigid state when axial compression is applied. Like some of the body portions described above, these interlocking features also permit the transmission of torsional forces in both the flexible and rigid states of the device. Being able to transmit torsional forces without excessive rotational displacement from one end of the implantable device to the other can be advantageous in various situations, such as during insertion or removal of the device, or when a surgeon desires to rotate the device to properly align it during installation in a bone. Additionally, the interlocking features of the exemplary embodiments shown are designed to resist tensile forces. This allows the surgeon to pull on the proximal end of the device without the device uncoiling or extending excessively in length.

As seen in the flexible-to-rigid body portion shown inFIGS. 99A and 99B, the interlocking features can comprise an alternating trapezoid ordovetail pattern7650 superimposed on a helical curve. As shown inFIGS. 99C and 99D, the interlocking features can comprise anomega shape7660.FIGS. 99E and 99F show that the interlocking features can comprisebulbous pendicles7670.FIGS. 99G and 99H show that the interlocking features can comprise an L-shape7680. Note that thegap7682 between features in one column is wider thangap7684 in the adjacent column, which in turn is wider thangap7686 in the next column. This progressive widening of gaps from one side of the flexible to rigid body portion to the other causes the body portion to curve when compressed, as will be further described below.FIGS. 99I and 99J show an example of T-shaped interlocking features7690. In other embodiments, a pattern of interlocking features can be continuous or intermittent. The interlocking features may also vary in a radial direction across the tube wall, and/or in an axial direction rather than, or in addition to, varying across the circumference of the tube as shown inFIGS. 99A-99J.

The body portions shown inFIGS. 99A-99J need not be curved when axially compressed as described above. Rather, they may be designed so that they compress equally on all sides of the center axis such that they form a straight segment when either flexible or rigid. Alternatively, the body portions may be designed to be curved when flexible, and compress in a uniform fashion such that they maintain their curved shape when transformed to a generally rigid state.

FIGS. 99A-99J provide exemplary geometries for a variety of cut patterns. The cross sectional geometry is shown as tubular. As discussed in more detail below, the cross sectional area can be of any shape tubular geometry or solid geometry. The specific cut pattern and cross sectional shape are selected and designed to match the anatomical shape of the bone or to provide specific fixation or reconstructive surfaces particularly suited to remediate the problem with the bone. Different cross sectional geometries are needed for the flat bones found in the face and skull, the ribs, the tibial plateau, the metacarpals, the metatarsals, and the scaphoid bone of the hand. The cut pattern can be “programmed” to reconstruct the bone into its anatomical configuration or into a modified configuration based upon the desired result of the remediation therapy. For instance, a reconstructive procedure may be prescribed to remediate a malunion of a bone. In this example the device, rather than collapsing upon activation lengthens and becomes rigid.

Although shown in the various embodiments of the figures is a device with grippers, it is also envisioned that the flexible-to-rigid member would collapse or extend such that axially successive geometries would be upset and driven radially outward. In is flexible state the cut patterns would freely bend relative to each other. Upon activation to the rigid state, for example, a crest of a wave pattern would be urged outward, thereby increasing the effective diameter of the device. The crest of the wave could be forced into the intramedullary bone and create a fixation moiety. One could envision a long tube where the crests of the wave patterns would be drive outward there by creating a high surface area of gripping power over the entire length of the device. Other pattern besides wave patterns could be made to do this.

FIGS. 100A and 100B depict the proximal end of adevice7100′ which is similar todevice100 and/or7100 previously described but incorporating the flexible-to-rigidtubular body portion7114′ ofFIG. 97.FIG. 100A showsdevice7100′ in a flexible, undeployed state, andFIG. 100B showsdevice7100′ in a generally rigid, curved state. To change between states afterdevice7100′ is inserted in the intramedullary cavity of a bone, the tip of a rotary driver tool (not shown) is inserted in keyedsocket7130 ofdrive member7128′ and rotated.Drive member7128′ is threadably engaged withshuttle7710.Shuttle7710 may be constructed in a flexible manner such thatbody portion7114′ remains flexible when in the undeployed state ofFIG. 100A.Shuttle7710 may include atab7712 at its proximal end that travels inslot7714 in the tube wall to preventshuttle7710 from rotating (as seen inFIG. 101D). Asdrive member7128′ is rotated by the driver tool,shuttle7710 is drawn towards the proximal end ofdevice7100′, as shown inFIG. 100A. The proximal end of atension wire7716 in turn is rigidly attached toshuttle7710. The distal end of tension wire7716 (not shown) may be coupled to a distal gripper as previously described, or attached to the distal end ofdevice7100′. Whentension wire7716 is drawn proximally byshuttle7710, V-shapedgaps7414 on thesecond side7412 ofbody portion7114′ are closed, causingbody portion7114′ to assume a curved shape as shown inFIG. 100B.

FIGS. 101A-101C show analternative embodiment device7100″ in various states.FIG. 101A showsdevice7100″ in a non-tensioned state,FIG. 101B shows a cross-section ofdevice7100″ in the non-tensioned state, andFIG. 101C shows a cross-section ofdevice7100″ in a tensioned state.

Device7100″ includes two flexible-to-rigidtubular body portions7114′,7114′ oriented in opposite directions. With this configuration, whenshuttle7710 andtension wire7716 are drawn proximally by rotatingdrive member7128,device7100″ assumes an S-shape, as shown inFIG. 101C. Thus,device7100″ may be used to repair S-shaped bones such as the clavicle. In a similar manner, the axial width, axial pitch and/or radial orientation of V-shapedcuts7414 can be varied to produce compound, varying curves in three dimensions to match any desired anatomy. For obtaining smaller radii of curvature, V-shapedcuts7414 that are more blunt may be used. The flexible to rigid body portions need not be of identical cross section. For example a round tubular section could be paired with a hexagonal tubular section. This would allow one section to rotate freely within the space it is located where the hexagonal structure would provide a form of resistance or registration.

FIGS. 101D and 101E show an S-formingdevice7100″′ similar todevice7100″ shown inFIGS. 101A-101C, but havingwavy slits7614 instead of straight V-shapedcuts7414.

FIG. 102 depicts an S-shaped device similar todevice7100″ deployed in aclavicle bone7910 across amid-shaft fracture7912.Device7101 may be configured with agripper7108 and/or one ormore screw holes7914 at its proximal end to securedevice7101 to one half ofclavicle7910. Similarly,device7101 may be configured with agripper7108 and/or one ormore screw holes7914 at its distal end to securedevice7101 to the other half ofclavicle7910.Body portions7114′,7114′ are configured such that they are flexible when being introduced intoclavicle7910. When grippers7108,7108 are deployed andbody portions7114′,7114′ become rigid as described above,device7101 assumes an S-shape that closely matches the contour of the intramedullary cavity withinclavicle7910. Such a configuration allowsdevice7101 to morerigidly support clavicle7910 for healing offracture7912 while avoiding undue forces onclavicle7910.

FIG. 103 showsdevice7101 described above and depicted inFIG. 102 as it is being introduced into a fracturedclavicle7910.

FIG. 104 shows an alternativeshape conforming device7103.Device7103 forms a simple curve when flexible-to-rigid body portion7114″ (also shown inFIG. 98A) is in a rigid state.Device7103 includes agripper7108′ at its distal end, having opposingtube segments8110,8110 that rotate to engage the bone whengripper7108′ is deployed.Device7103 also has atripod gripper7108″ at its proximal end, having three pairs ofscissor arms8112,8112,8112 for engaging the bone when actuated. Further details ofgrippers7108′ and7108″ are provided in application Ser. No. 11/944,366 referenced above.

FIG. 105 shows an alternative shape conforming device7105. As shown, device7105 forms an S-shape when flexible-to-rigid body portions7114″ are in a rigid state. The distal end of device7105 may be secured to the bone bygripper7108, and the proximal end may be secured with bone screws through the device.

In alternative embodiments,grippers7108 andscrew7110 attachment provisions may be omitted from one or both ends of the device. In these embodiments, the curved nature of body portion(s)7114′ is enough to secure the device end(s) within the bone and hold the fracture(s) in place. In embodiments with and withoutgrippers7108 andscrews7110, the anatomy-conforming curve may serve to grip the bone and approximate the fracture(s). In many embodiments, the action of the closing of the slots (such as7116) during axial compression also serves to grip the bone and/or approximate the fracture(s). In other embodiments, wire or other fastening elements may be used to secure the device in place.

Referring now toFIGS. 106-114, another exemplary embodiment of a bone fixation device constructed according to aspects of the present invention will be described.FIG. 106 showsbone fixation device8300 attached to an insertion andremoval tool8302 andactuation tool8304. Insertion andremoval tool8302 in turn is mounted in afixture arm8306.

Referring toFIG. 107, components ofbone fixation device8300 and insertion andremoval tool8302 are shown. In this exemplary embodiment,device8300 comprises ahub8402,actuation screw8404,actuation shuttle8406, flexible-to-rigid body member(s)8408,tension member8410, andend cap8412. In alternative embodiments, additional, fewer, or a single flexible-to-rigid body member may be used. Insertion andremoval tool8302 comprisessleeve8450,tube8452,knob8454, and may be mounted thoughfixture arm8306.

Referring toFIG. 108, an enlarged perspective view of the assembleddevice8300 is shown.

Referring toFIG. 109, an enlarged, cut-away perspective view shows internal components ofdevice8300.End cap8412, having the same nominal outer diameter as flexible-to-rigid body member(s)8408 (shown inFIG. 108), is rigidly connected, such as by welding, to the distal end oftension member8410.Tension member8410 is sized to fit within flexible-to-rigid body member(s)8408.Tension member8410 may include a central longitudinal lumen, the purpose of which is later described.Tension member8410 may also be provided with a series oflongitudinal slots8610 through its wall thickness to allow it to be very flexible.Solid ring portions8612 may be interspersed between the series ofslots8610 to retain the tubular shape and torsional rigidity oftension member8410. In other embodiments (not shown), the tension member is formed from one or more wires or cables, which may be bundled together, to be strong in tension while being flexible in bending.

Actuation shuttle8406 is attached to the proximal end oftension member8410, such as by welding.Actuation shuttle8406 includes aknobbed end8710, as seen inFIG. 110A.Knobbed end8710 is configured to be received withinmating keyhole8712 in one side ofactuation screw8404, as seen inFIGS. 110B and 110C.Actuation shuttle8406 may also include a radially-protrudingtab8714, as seen inFIG. 110A.Tab8714 is sized to slide in alongitudinal slot8510 indevice hub8402, as seen inFIG. 108, to allowactuation shuttle8406 to move axially without rotation. Withactuation shuttle8406 rotatably received inactuation screw8404, which in turn is threadably engaged withhub8402, the distal end ofactuation tool8304 may be received (as seen inFIG. 111) in a keyed recess8716 (seen inFIG. 110C) ofactuation screw8404. Turningactuation screw8404 withactuation driver8304 causesactuation screw8404, and with itactuation shuttle8406, to move axially with respect tohub8402. Asactuation shuttle8406 moves in a proximal direction (away from distal end cap8412), a tensile force is imparted totension member8410, causing flexible-to-rigid body member(s)8408 to be axially compressed betweenend cap8412 and hub8402 (seeFIGS. 108 and 109). As previously described, this compression causes body member(s)8408 to become substantially rigid, and to take on a predetermined shape, as will be more fully described below.

Referring toFIG. 110E, a plan view of an interlocking pattern is shown. The pattern has the same interlocking L-shapedfeatures7680 as the flexible-to-rigid body member8408 shown inFIGS. 99G and 99H described briefly above. In other words,FIG. 110E represents the pattern that would result if thebody member8408 were slit along one side in a longitudinal direction, unrolled and laid flat.Arrows8710 inFIG. 110E indicate the longitudinal or axial direction of the pattern, whilearrows8712 represent the tangential direction. As can be seen, the pattern is formed by a continuous helical cut, such thatgap8722 on one side of the pattern connects withgap8724 on the other side of the pattern when the pattern is formed on a tubular structure. While a single helical cut is shown, other embodiments may employ two or more helical cuts running in parallel around the tube. Pattern gaps may be formed by laser cutting, punching, milling, etching, sawing, electro-discharge machining, or other material removal or material addition processes. Patterns may be formed on a tubular structure, or on a generally flat substrate which is then configured into a tubular structure.

As briefly mentioned above in conjunction withFIG. 99G, the interlocking pattern may utilize gaps that narrow along one side of the tube (shown in the center ofFIG. 110E) and widen along the other side of the tube (shown at the sides ofFIG. 110E). In this exemplary pattern,gaps7682 are wider thangaps7684, which in turn are wider thangaps7686, which in turn are wider thangap8726. As the pattern is compressed in an axial direction when formed on a tubular structure, the features adjacent the wider gaps (e.g.7682) will move farther than the features adjacent the narrower gaps (e.g.8726) as the gaps are closed. Since one side of the tube is compressing more than the opposite side, the tube forms a curve that is concave on the side having the widest gaps.

Referring again toFIGS. 107 and 108, and also toFIG. 111, if all of the flexible-to-rigid body members8408 are oriented with their widest pattern gaps on one side of thedevice8300, the flexible-to-rigid portion will take on a single curved shape. If thebody members8408 toward the distal end are all oriented with their widest pattern gaps on one side, and thebody members8408 toward the proximal end are all oriented with their widest gaps on the opposite side, a compound or S-shaped curve will result, as shown inFIG. 112. If the orientation of each successive body member is alternated from one side to the other and back again, a rapidly undulating curve will result. If the orientation of each successive body member is changed in phase, for example by 90 degrees, from the orientation of the previous body member, a helical arrangement of the overall flexible-to-rigid body portion may be achieved. It can be appreciated that by changing the orientation of the gap thicknesses, essentially any desired three-dimensional curve may be obtained to suit the particular purpose. For example, the rapidly undulating curve described above may be more useful in some circumstances for allowing a bone fixation device to gain purchase within a relatively straight intramedullary canal. A body member having a compound curve can be useful in a bone fixation device that is designed to be inserted in a radius or an ulna, as these bones curve in more than one plane simultaneously. A bone fixation device having an S-shaped curve is useful in bones that have S-shaped portions, such as the clavicle.

It should be noted that in addition to varying the gap orientation, the relative change in gap width may be varied to produce curves of different radii. For example, one portion of a flexible-to-rigid body may have the same gap width around its circumference to produce a straight section, another portion may have a relatively small change in gap width to produce a large radius of curvature, while yet another portion may have a larger change in gap width around its circumference to produce a small radius of curvature. In some embodiments, such as shown in the accompanying figures, the device may employ a series ofindividual body members8408 that together form an overall flexible-to-rigid body portion. Alternatively, it should be noted again that a continuous complex pattern similar to that formed by the multiple body sections described above may be formed on a single tubular structure. Additionally, interlocking or non-interlocking features other than the L-shapedfeatures7680 may be used in addition to or instead offeatures7680.

Referring toFIGS. 113 and 114, use of thebone fixation device8300 and associated tools with aguide wire9010 is described. As described above and shown in the accompanying figures, each of the central components ofdevice8300 has an axial lumen extending therethrough. Similarly, the central components ofactuation tool8304 have an axial lumen extending therethrough. This arrangement permitsdevice8300, insertion/removal tool8302, and/oractuation tool8304 to be slid, either individually or together, overguide wire9010.

In some bone fixation operations, it is advantageous to first introduce a guide wire into the intramedullary space of a bone before inserting abone fixation device8300, and in some cases before preparing the intramedullary canal for receivingdevice8300. According to aspects of the invention, in some methods an access incision or puncture is made in the tissue surrounding a bone. A pilot hole may then be drilled in the bone to gain access to the intramedullary canal.Guide wire9010 may then be introduced through the pilot hole (or in some cases without a pilot hole) into the intramedullary space.Guide wire9010 may be further advanced through the canal and across a fracture site or sites, lining up bone fragments along the way. Introduction ofguide wire9010 may take place with the aid of fluoroscopy or other imaging technique.

Afterguide wire9010 is inserted into a target bone, various burs, cutters, reamers, trocars, and/or other bone forming or aligning tools may be alternately advanced overguide wire9010. One an interior bone space has been prepared (if desired) to receivebone fixation device8300,device8300 along with insertion/removal tool8302 andactuation tool8304 may be advanced over guide wire8210. Insertion/removal tool8302 may first be inserted infixture arm8306, which in turn may be fastened to external fixtures or used as a handle to assist in steadying and aligningdevice8300 during insertion and actuation.Device8300 may then be advanced alongguide wire9010 and into position within the bone. The guide wire may occupy a central lumen of the device along its longitudinal axis. The guide wire may slide along openings in the outer diameter surface of the device in an analogous fashion to the eyelets of a fishing rod. These lumen may be intra-operatively or post-operatively available for the delivery of other devices, therapies to the bone, or tools.

Deployment ofdevice8300 may be accomplished by rotatingactuation tool8304. As previously described, such rotation movesactuation screw8404 in a proximal direction and ultimately causes a compressive load to be placed on flexible-to-rigid body portion(s)8408. This in turn causes flexible-to-rigid body portion(s)8408 to take on a desired shape and become generally rigid to securedevice8300 against the interior surfaces of the bone.Actuation tool8304 may include a torque measuring or limiting mechanism to help ensure that a predetermined or desired amount of force is being applied from deployeddevice8300 against the bone.Device8300 may be secured with additional methods, such as with bone screw(s), K-wire(s) and the like.

Actuation tool8304 and insertion/removal tool8302 may be removed together or individually.Actuation tool8304 is removed be pulling in a proximal direction to disengage its distal tip fromrecess8716 withinactuation screw8404. Insertion/removal tool8302 is disengaged fromdevice8300 by turning the knob at the proximal end oftool8302. This unscrews the externally threaded distal tip oftube8452 oftool8302 from the internally threaded bore ofhub8402, as seen inFIG. 114. The guide wire8210 may then be removed (or at an earlier time if desired), and the access wound(s) closed. It will be appreciated that these same tools and the reverse of these methods may be used to removedevice8300, if desired, during the initial procedure or at a later time.

Referring toFIGS. 115 and 116, additional exemplary patterns are shown that may be used in the flexible-to-rigid body portions of bone fixation devices.Non-repeating pattern9200 includes ten different interlocking shape pairs along ahelical slit9202, none of which are the same. In thisexample pattern9200, there are two interlocking shape pairs located along each revolution ofhelical slit9202, such that when the pattern is formed on a tube, the two pairs are on opposite sides of the tube. Alternatively, a pattern of interlocking shapes may repeat every revolution of thehelical slit9202, every partial revolution, or over the course of more than one revolution. For example, a series of six different interlocking shape pairs may repeat every three revolutions ofhelical slit9202, as shown in theexemplary pattern9300 ofFIG. 116.

It can be seen inFIGS. 115 and 116 thatpatterns9200 and9300 include rampedportions9204 along each revolution ofhelical slit9202 where the slit gets progressively wider. Additionally,helical slit9202 forms a wider gap adjacent to the lower set of interlocking shape pairs9206 than it does adjacent to the upper set of shape pairs9208. These rampedportions9204 and wider gaps allowpatterns9200 and9300 to axially compress to a greater extent in one area (the lower part ofFIGS. 115 and 116) than in another area (the upper part ofFIGS. 115 and 116). Accordingly, whenpatterns9200 and9300 are applied to a tubular member, the member will form a curve when axially compressed, as previously described.

Referring toFIGS. 117A-117H, an alternative flexible-to-rigidbody portion pattern9400 will now be described.Pattern9400 is formed by superimposing a sinusoidal pattern onhelical slit9402. Helical slit9402 may be continuous, or it may be formed in individual segments with solid sections in between, as shown inFIG. 117A. In can be seen inFIG. 117A that thepeak9404 on one side ofslit9402 nests withintrough9406 on the opposite side ofslit9402.

Referring toFIG. 117B, it can be seen that slit9402 may be formed at an angle relative totube wall9408 rather than being perpendicular totube wall9408 and the longitudinal axis of the device. In this manner, a ramp is formed on thepeak side9404 ofslit9402 and another ramp is formed on thetrough side9406. In other embodiments, a ramp may be formed only on thepeak side9404 or only on thetrough side9406. In some embodiments, only a portion of one or both sides is ramped or rounded. When the flexible-to-rigid body portion is axially compressed, the ramps cause at least atip portion9410 of peak9404 to ride up ontrough9406 and extend radially outward, as shown inFIG. 117C. This tip portion may be configured to bite into the surrounding bone. Even if each extendingtip9410 only provides a small amount of gripping force, with a large number oftips9410 engaging the bone a large amount of gripping power can be generated to hold the device within the bone. In the embodiment shown inFIG. 117C, only a portion of thetube wall9408 on one side ofslit9402 rides above thetube wall9408 on the opposite side ofslit9402. In other embodiments, one side oftube wall9408 may ride up and completely onto the opposite side.

Referring toFIGS. 117D-117G,tip9410 need not take the shape of a sinusoidal wave. The tip may be V-shaped (FIG. 117D), semicircular (FIG. 117E), chisel-shaped (FIG. 117F), square (FIG. 117G), notched (FIG. 117H), or have another shape in order to effectively grip the surrounding bone. Tips of a particular device may have the same shape on every tip, or multiple tip shapes may be used on one device.

While bone fixation devices having circular cross-sections have been shown and described, other cross-section shapes according to aspects of the invention may be useful in some circumstances. In some embodiments, a triangular cross-section may be used, as its sharp edges can aid in gripping the surrounding bone. Non-circular cross sections may be used in applications where a particular combination of area moments of inertia is desired. Particular non-circular cross sections may be chosen for their optimization in certain anatomies, or for aiding in manufacturability of a bone fixation device. In some embodiments, the cross section of the bone fixation device is circular, oval, elliptical, triangular, square, rectangular, hexagonal, octagonal, semi-circular, crescent-shaped, star-shaped, I-shaped, T-shaped, L-shaped, V-shaped, or a combination thereof. In some embodiments, the cross section forms a polygon having any number of sides from 1 to infinity. In some embodiments, the cross-sections are tubular and in others they are solid. In some embodiments, the cross-section of the device can vary in size along it length, such as tapering from the proximal end to the distal end.FIGS. 118A-118D provide an example of an oval cross section, andFIGS. 119A-119D provide an example of a square cross-section.

In other embodiments, a solid rectangular geometry with an externally communicating stiffening member can be constructed.FIGS. 120A-120E,FIGS. 121A-121E andFIGS. 122A-122B describe three exemplary geometries. The external stiffener geometry of the device shown inFIGS. 120A-120E, and its resultant shape upon activation to its rigid state, are designed to allow insertion, match the anatomical configuration of the bone, and provide remediation of the malady of the bone, such as proximation and fixation of the fracture. The external stiffener geometry of the device allows removal upon deactivation. The devices shown inFIGS. 120 through 122 may be used for treatment of flat bones, such as those of the face, skull, scapula, and lateral clavicle.

In various embodiments, a fracture fixation system comprises a system of one or more implants, devices and instruments configured for the repair of fractures of a bone from within an intramedullary canal. In some embodiments, asegmented implant10000 has rigid and flexible configurations. In some embodiments, asegmented implant10000 has a curved configuration and a straightened configuration. In some embodiments, ansegmented implant10000 includes one or more flexible-to-rigid body portions10100 with any or all features according to any of the embodiments disclosed herein, including but not limited to a flexible-to-rigid body portion114,3114,3208,3306,4406,4504,4604,4704,4804,4904,5000,5100,5102,5200,5300,5400,6304,7114,7650,7660,7670,8408,9400, T-shaped interlocking features7690,hub3600,3650,3700,3750, and/orpattern9200. In some embodiments, a segmented flexible-to-rigid body portion10100 is flexible upon entry into bone and rigid upon application of compressive axial force provided by an instrument, such as in one embodiment, a tensioning actuator. In various embodiments, segmented flexible-to-rigid body portion10100 has a polygonal cross sectional geometry having any suitable number of sides from 1 to infinity. In various embodiments, segmented flexible-to-rigid body portion10100 may be manufactured or configured in a specific way so that upon activation it conforms to a specific shape. The resultant shape may resemble or match the original anatomical shape of the bone. The resultant shape may provide specific translational actions so as to improve the healing of bone or create a resultant bone-implant construct that promotes a desired resultant geometry or effect. These resultant geometries may be bone lengthening where growth of the bone is improper, bone rotation to remediate poor pronation, supination, deflection, extension, deviation, or inclination of an appendage or joint. In various embodiments, segmented flexible-to-rigid body portion10100 may be devised or designed from x-ray or CT scans of the contralateral unaffected anatomy to return the affected anatomy to its original anatomical configuration or match the existing contralateral configuration.

In various embodiments, segmented flexible-to-rigid body portion10100 comprises a single-piece design that is parsed into individual segments to maximize the transformation of the same body from a very flexible member that minimizes strength in bending to a rigid body that maximizes strength in bending and torque. In some embodiments, one or more segments are from one or more separate materials. In various embodiments, segmented flexible-to-rigid body portion10100 transforms to a rigid member when compressive forces are applied in the axial direction at each end, such as by an actuator. In various embodiments, segmented flexible-to-rigid body portion10100 is formed from one or more cuts on a tubular member at an angle of incidence to the axis somewhere between 0 and 180 degrees from the longitudinal axis of a tubular body portion. In various embodiments, segmented flexible-to-rigid body portion10100 is formed from one or more cuts on one or more flat materials that can be formed in to a tube or closed shape. In various embodiments, the cuts can be altered in depth and distance between the cuts (i.e. thickness) on the longitudinal axis along the length of a tube or flat material to variably alter the flexible-to-rigid characteristics of the segmented flexible-to-rigid body portion10100 along its length. In some embodiments, one ormore segments10200 include a lumen or cannula along a longitudinal axis of theimplant10000. In some embodiments, one ormore segments10200 have one or more thicknesses and/or dimensions that can be constant or change.

In various embodiments, segmented flexible-to-rigid body portion10100 includes two ormore segments10200. In various embodiments, segmented flexible-to-rigid body portion10100 includes 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 50 ormore segments10200. In some embodiments,segments10200 are formed from different materials. In some embodiments,segments10200 are formed from common materials. In some embodiments,segments10200 are separated by acut10110. In some embodiments, a cut refers to any machining, casting, or manufacturing for forming one or more edges. In some embodiments,segments10200 have one ormore edges10112. In some embodiments, edges10112 are formed withcuts10110. In some embodiments, edges10112 are formed independently of cuts. In some embodiments, edges10112 follow a pattern. In some embodiments, edges10112 do not have a pattern. In some embodiments, edges10112 may have a repeating pattern, or a non repeating pattern. In one embodiment, patternededges10112 can include one or more inter-digitations10114 (e.g., portions that are interlocking). In some embodiments, one ormore edges10112 betweenadjacent segments10200 may include one or more gaps. In some embodiments, one ormore edges10112 may function to dictate the radius of curvature and/or the chord length of the geometry of the flexible-to-rigid body portion10100 in its rigid state. In some embodiments, one ormore edges10112 may be sized and configured such that the geometry in the rigid shape fits or matches the anatomical curvature of the specific bone into which it will be implanted. In some embodiments, edges10112 may function to prevent axial displacement or excessive elongation of the flexible-to-rigid body portion10100. In some embodiments, one ormore edges10112 may function to prevent the flexible-to-rigid body portion10100segments10200 from disconnecting and allow for the removal of thesegmented implant10000 from a bone. In some embodiments, the edges may be sized and configured to withstand up to about 100, 150, 200, 250, 275, 300, 400, 500 or more pounds-force. In some embodiments, inter-digitations10114 may also function to prevent axial displacement or excessive elongation of the flexible-to-rigid body portion10100 and in some instances, they may provide torsional resistance, especially when the elongate body is curved and in a rigid state.

In various embodiments,segments10200 in a flexible-to-rigid body portion10100 allow an otherwiserigid implant10000 to increase its flexibility to a large degree during deployment and/or retrieval. In various embodiments,segments10200 can have constant or varying internal and external diameters and/or dimensions. Application and removal of compressive forces provided by an instrument, member, wire, tension ribbon, sheath, or actuator can transform the flexible-to-rigid body portion10100 from flexible to rigid and vice versa.

In various embodiments,segments10200 and/orgaps10210 may be formed by laser cutting, punching, milling, etching, sawing, electro-discharge machining, or other material removal or material addition processes. In various embodiments, patterns may be formed on a tubular structure, or on a generally flat substrate which is then configured into a tubular structure. In various embodiments,segments10200 can be formed from any material, including but not limited to metal, stainless steel, shape-memory metal, Nitinol, titanium, a polymer, or any other material disclosed herein.

FIGS. 123 and 127 illustrate various embodiments of a segmented flexible-to-rigid body portion10100 in plan view, laid flat. In various embodiments, the flexible-to-rigid body portion10100 can be cut from a tube or cut then formed into a shape and attached (e.g. welded, etc.). In various embodiments, the flexible-to-rigid body portion10100 axial compression can cause the proximally and distally extending features to translate transverse to the longitudinal axis of theimplant10000. This lateral movement causes keying features formed on the extending features to inter-engage, aiding in the rigidity of the construct.

In some embodiments, one ormore edges10112 betweenadjacent segments10200 can form one ormore gaps10210. In some embodiments,gaps10210 are uniform betweensegments10200. In some embodiments,gaps10210 varied in size and/or dimension to increase flexibility of the flexible-to-rigid body portion10100 in one or more planes or directions. In some embodiments, one ormore gaps10210 can get progressively smaller as shown inFIG. 123 andFIG. 127. When the flexible-to-rigid body portion10100 is axially compressed, it forms a curve between in eachsegment10200 in which thegap10100 is varied. The resulting shape is a curve which extends along the length of the flexible-to-rigid body portion10100. In some embodiments, this shape aids theimplant10000 in being able to move, become positioned in, and/or grip the interior surfaces of the bone.

In one embodiment, one ormore gaps10210 are narrow along one side of the flexible-to-rigid body portion10100 (shown in the center ofFIG. 124) and widen along the other side of the tube (shown at the center ofFIG. 125). As thesegments10200 are compressed in an axial direction, the features adjacent the wider gaps will move farther than the features adjacent the narrower gaps as the gaps are closed. Since one side of the flexible-to-rigid body portion10100 is compressing more than the opposite side, the flexible-to-rigid body portion10100 forms a curve that is concave on the side having the widest gaps.

Referring again toFIGS. 124 and 125, in one embodiment, all of thesegments10200 are oriented with theirwidest pattern gaps10210 on one side of the flexible-to-rigid body portion10100, the flexible-to-rigid body portion10100 will take on a single curved shape. In one embodiment,segments10200 toward the distal end of the flexible-to-rigid body portion10100 are all oriented with their widest pattern gaps on one side, andsegments10200 toward the proximal end of the flexible-to-rigid body portion10100 are all oriented with their widest gaps on the opposite side, a compound or S-shaped curve will result. In one embodiment, if the orientation of eachsuccessive segment10200gap10210 is alternated from one side to the other and back again, an undulating curve will result. If the orientation of each successive segment or gap is changed in phase, for example by 90 degrees, from the orientation of the previous segment or gap, a helical arrangement of the overall flexible-to-rigid body portion10100 may be achieved. In various embodiments, changing the orientation of thegap10210 thicknesses can be used to generate any desired three-dimensional curve to suit the particular purpose. In various embodiments, different flexible-to-rigid body portion10100 shapes may be more useful in some circumstances for allowing a bone fixation device to gain purchase within a relatively straight intramedullary canal. A flexible-to-rigid body portion10100 having a compound curve can be useful in a bone fixation device that is designed to be inserted in a radius or an ulna, as these bones curve in more than one plane simultaneously. A bone fixation device having an S-shaped curve is useful in bones that have S-shaped portions, such as the clavicle.

In various embodiments, in addition to varying thegap10210 orientation, the relative change ingap10210 width may be varied to produce overall flexible-to-rigid body portion10100 curves of different radii. For example, in one embodiment, one portion of a flexible-to-rigid body portion10100 may have the same gap width around its circumference to produce a straight section, another part of the flexible-to-rigid body portion10100 may have a relatively small change in gap width to produce a large radius of curvature, while yet another part of the flexible-to-rigid body portion10100 may have a larger change in gap width around its circumference to produce a small radius of curvature.

In some embodiments, a segmented flexible-to-rigid body portion10100 of asegmented implant10000 can optionally include one or morebone engaging mechanisms10300 according to any of the embodiments of the various bone engaging mechanisms herein. In one embodiment, a bone engaging mechanism is a gripper. In some embodiments, one or morebone engaging mechanisms10300 deploy when the flexible-to-rigid body portion10100 is in a curved configuration. In some embodiments, one or morebone engaging mechanisms10300 deploy when the flexible-to-rigid body portion10100 is in a straightened configuration. In some embodiments, one or morebone engaging mechanisms10300 deploy independently of the configuration of the flexible-to-rigid body portion10100. Although various illustrated embodiments ofsegmented implants10000 include one or morebone engaging mechanisms10300, in one embodiment, asegmented implant10000 has nobone engaging mechanism10300.

In one embodiment, illustrated atFIGS. 128-136, a segmented flexible-to-rigid body portion10100 of asegmented implant10000 includes discrete, individual segmented links, orsegments10200. In one embodiment, in a deactivated state, the segmented flexible-to-rigid body portion10100 is flexible. When actuated, the segmented flexible-to-rigid body portion10100 becomes rigid by collapsing or compressing thesegments10200 against one another. In one embodiment, eachindividual segment10200 is decoupled from the adjoiningsegments10200. In one embodiment, the geometry of thesegments10200 is configured such that when actuated, the segmented flexible-to-rigid body portion10100 can take on a predetermined geometry. In one embodiment, segmented flexible-to-rigid body portion10100 has a different shape or geometry when it is in a flexible state and when it is in an actuated state. In some embodiments, a segmented flexible-to-rigid body portion10100 includes two or more individual decoupledsegments10200, interlocking geometry betweensegments10200, an asymmetric inter-segment gap that provides a change in geometry (curvature and length) between the actuated and deactuated states, some or all of which help provide for a more efficient actuation and more rigid body when compared to other geometries/configurations. In various embodiments, different combinations of materials, segment geometry, the number and geometry of the interlocking feature(s), various inter-segment gap patterns (both symmetric and asymmetric), varying number of individual segments and other characteristics may be used.

In one embodiment,adjacent segments10200 are individual decoupled links that are joined together by an interlocking geometry. In various embodiments, the interlocking geometry can be any of the L-shaped, T-shaped, wedge shaped, or other interlocking geometries disclosed herein. In some embodiments, the interlocking geometry provides structural integrity when actuated and during insertion and removal of theimplant10000. In some embodiments, the interlocking geometry provides tensile strength to the construct. In one embodiment, a segmented flexible-to-rigid body portion10100 of asegmented implant10000 includes individual segmented links that when actuated provide a rigidity and geometry different than that of the deactuated state. In various embodiments, a cut pattern or inter-segment gap may be a symmetric or asymmetric, non-helical pattern. In one embodiment an edge pattern/inter-segment gap is asymmetric. This gives the segmented flexible-to-rigid body portion10100 the ability to take on a different shape/geometry once actuated. For example, as illustrated inFIGS. 134-136, the curvature and length of various embodiments ofimplants10000 with different numbers and/or types ofsegments10200 can change from the deactuated state to the actuated state. In various embodiments, the number of segments, individual segment geometry and inter-segment gap can be altered to provide various constructs for different applications.

Example 1

The following example is intended to be a non-limiting embodiment of the invention.

As illustrated atFIGS. 137-140, it was experimentally verified that an embodiment of a segmented flexible-to-rigid body portion10100 of asegmented implant10000 had improved loading characteristics when compared to anon-segmented implant10000. In an experimental set up, a non-segmented, helical flexible-to-rigid body portion of an implant was subjected to various loading conditions and compared to a segmented flexible-to-rigid body portion10100 of asegmented implant10000 with a non-“T” shaped interlocking geometry (T-less), and compared to a segmented flexible-to-rigid body portion10100 of asegmented implant10000 with a “T” shaped interlocking geometry. Each of the three implants have the same length in the deactuated/straightened state.

FIG. 137 illustrates chart illustrating results from an experimental setup with various embodiments of implants of the present invention, comparing the cycles to failure based the same combined load (with bending and torsion). In the experiment, the non-segmented, helical implant had roughly 108,000-110,000 cycles from bending and torsion before failure. In the experiment, the T-less segmented implant had roughly 104,000-107,000 cycles from bending and torsion before failure. In the experiment, the “T” shaped interlocking geometry segmented implant had roughly 158,000-162,000 cycles from bending and torsion before failure. Thesegmented implant10000 with a “T” shaped interlocking geometry reflects a roughly 60% increase in cycles to failure when compared to the other implants.

FIG. 138 illustrates chart illustrating results from an experimental setup with various embodiments of implants of the present invention, comparing the cycles to failure based the same bending load. In the experiment, the non-segmented, helical implant had roughly 103,000-108,000 cycles from bending before failure. In the experiment, the T-less segmented implant had roughly 140,000-145,000 cycles from bending before failure. In the experiment, the “T” shaped interlocking geometry segmented implant had roughly 205,000-210,000 cycles from bending before failure. Thesegmented implant10000 with a “T” shaped interlocking geometry reflects a roughly 100% increase in cycles to failure when compared to the non-segmented helical implant. Thesegmented implant10000 with a “T-less” interlocking geometry reflects a roughly 40% increase in cycles to failure when compared to the helical, non-segmented implant.

FIG. 139 illustrates chart illustrating results from an experimental setup with various embodiments of implants of the present invention, comparing the static tension load (in pounds force) to failure. In the experiment, the non-segmented, helical implant was subjected to roughly 235-245 pounds force in tension before failure. In the experiment, the T-less segmented implant was subjected to roughly 120-125 pounds force in tension before failure. In the experiment, the “T” shaped interlocking geometry segmented implant was subjected to roughly 255-265 pounds force in tension before failure. Thesegmented implant10000 with a “T” shaped interlocking geometry reflects a roughly 10% increase in torsion loading prior to failure when compared to the helical, non-segmented implant. Thesegmented implant10000 with a “T” shaped interlocking geometry reflects a roughly 100% increase in torsion loading prior to failure when compared to the T-less shaped interlocking geometry implant.

FIG. 140 illustrates chart illustrating results from an experimental setup with various embodiments of implants of the present invention, comparing the static torque load (in inch pounds) to failure. In the experiment, the non-segmented, helical implant was subjected to roughly 10-11 lbf-in in static torque before failure. In the experiment, the T-less segmented implant was subjected to roughly 20-22 lbf-in in static torque before failure. In the experiment, the “T” shaped interlocking geometry segmented implant was subjected to roughly 25-26 lbf-in in static torque before failure. Thesegmented implant10000 with a “T” shaped interlocking geometry reflects a roughly 250% increase in torque loading prior to failure when compared to the helical, non-segmented implant. Thesegmented implant10000 with a “T” shaped interlocking geometry reflects a roughly 15-20% increase in torque loading prior to failure when compared to the T-less shaped interlocking geometry implant.

Overall, it was experimentally verified that a segmented implant with a “T” interfacing geometry provided more durability and/or resistance to failure in bending loads alone, and with tension and in bending loads in combination when compared to “T-less” interface geometry and non-segmented helical implants. The “T” interfacing geometry provided more durability and/or resistance to failure in static tension loading, as well as in torque loading. The individual segments, when actuated allow for a more efficient actuation. When actuated, the segmented construct appears to provide a more rigid construct compared to other geometries.

As illustrated inFIGS. 141-146, in various embodiments, asegmented implant10000 with a flexible-to-rigid body portion10100 further includes a flexible-to-rigid body sleeve10400 configured for placement over the flexible-to-rigid body portion10100. In various embodiments, a flexible-to-rigid body sleeve10400 is an optional component that can partially or fully enclose a flexible-to-rigid body portion10100. In various embodiments, a flexible-to-rigid body sleeve10400 is configured to wrap or partially wrap a flexible-to-rigid body portion10100. In one embodiment, the flexible-to-rigid body sleeve10400 is integral with the flexible-to-rigid body portion10100. In one embodiment, the flexible-to-rigid body sleeve10400 is integral with thesegmented implant10000. In one embodiment, the flexible-to-rigid body sleeve10400 is separate from with the flexible-to-rigid body portion10100. In one embodiment, the flexible-to-rigid body sleeve10400 is separate from thesegmented implant10000. In various embodiments, a flexible-to-rigid body sleeve10400 is flexible.

As shown inFIGS. 142-143 and144-146, in various embodiments, a flexible-to-rigid body sleeve10400 is configured to cover at least a part of a flexible-to-rigid body portion10100 for providing a smoother surface for easier installation and/or removal of thesegmented implant10000 in bone, tissue, or a body. In one embodiment, a flexible-to-rigid body sleeve10400 is configured to cover at least onesegment10200, cut10110,edge10112,inter-digitation10114, gap, or other part of a flexible-to-rigid body portion10100 to provide a smoother surface that is easier to install and/or remove from a body. In various embodiments, a flexible-to-rigid body sleeve10400 is configured to cover at least a part of a flexible-to-rigid body portion10100 to keep parts of the flexible-to-rigid body sleeve10400 contained within thesegmented implant10000. In one embodiment, a flexible-to-rigid body sleeve10400 is configured to cover at least onesegment10200, cut10110,edge10112,inter-digitation10114, gap, or other part of a flexible-to-rigid body portion10100 to prevent exposure, separation, detachment, and/or release of any part from thesegmented implant10000 in to a bone.

In various embodiments, the flexible-to-rigid body sleeve10400 is made of a metal, non-metal, plastic, rubber, composite, or other material. In some embodiments, the flexible-to-rigid body sleeve10400 is made of stainless steel. In one embodiment, the flexible-to-rigid body sleeve10400 is tubular. In various embodiments, the flexible-to-rigid body sleeve10400 has a wall thickness of 0.001-0.5, 0.01-0.1, 0.01-0.05, or other thicknesses in inches, centimeters, or millimeters. In one embodiment, the flexible-to-rigid body portion10100 has one or more reduced outer diameter features or portions configured to hold the flexible-to-rigid body sleeve10400 in place. In one embodiment, the flexible-to-rigid body portion10100 has one or more reduced outer diameter features or portions creating an undercut or keyed feature or interface to hold the flexible-to-rigid body sleeve10400 in place. In one embodiment, the flexible-to-rigid body portion10100 has one or more reduced outer diameter features or portions creating an undercut or keyed feature or interface that matches the thickness of the wall of the flexible-to-rigid body sleeve10400. In various embodiments, the flexible-to-rigid body sleeve10400 slides over the flexible-to-rigid body portion10100. In various embodiments, the flexible-to-rigid body sleeve10400 is configured to stretch, bend, and/or radially expand and/or contract. In various embodiments, the flexible-to-rigid body sleeve10400 is configured to be welded, glued, pinned, screwed, adhered, attached, crimped, snap-fit, enclosed, expanded over, and/or connected to the flexible-to-rigid body portion10100. In various embodiments, one or more ends, any part, or all of the flexible-to-rigid body sleeve10400 is attached to the flexible-to-rigid body portion10100.

In various embodiments, the flexible-to-rigid body sleeve10400 is cylindrical. In various embodiments, the flexible-to-rigid body sleeve10400 has alumen10410. In various embodiments, the flexible-to-rigid body sleeve10400 is a tube. In various embodiments, the flexible-to-rigid body sleeve10400 is a mesh. In various embodiments, the flexible-to-rigid body sleeve10400 has one ormore slots10420. In one embodiment aslot10420 is a hole of any shape. In various embodiments, the flexible-to-rigid body sleeve10400 has a plurality ofslots10420 over part or all of the sleeve. In various embodiments, theslot10420 is configured to provide the flexible-to-rigid body sleeve10400 with flexibility for attachment and/or detachment from the flexible-to-rigid body portion10100. In various embodiments, theslot10420 has a slot dimension (such as height, width, depth, radius, diameter, shape, thickness, etc.) configured to contain or hold asegment10200, cut10110,edge10112,inter-digitation10114, gap, or other part of a flexible-to-rigid body portion10100 within thelumen10410. As shown inFIG. 141, in one embodiment, theslot10420 is a spiral. In one embodiment, theslot10420 is a helical cut.

While various embodiments of the present invention have been shown and described herein, it will be noted by those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It will be understood that the foregoing is only illustrative of the principles of the invention, and that various modifications, alterations, and combinations can be made by those skilled in the art without departing from the scope and spirit of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.

Claims (25)

What is claimed is:

1. A segmented bone fixation device comprising:

an elongate body having a longitudinal axis and a flexible-to-rigid portion, the flexible-to-rigid portion comprising a plurality of segments, the flexible-to-rigid portion being flexible in a first state and being generally rigid in a second state which allows the elongate body to go between a flexible state to a rigid state;

an actuatable bone engaging mechanism disposed within the elongate body, wherein the bone engaging mechanism comprises a gripper having at least one bendable member such that as the gripper is actuated, the bendable member pivots away from the longitudinal axis of the elongate body and the gripper is deployed from a retracted configuration to an engaged configuration; and

an actuator operably connected to the bone engaging mechanism to actuate the bone engaging mechanism from a disengaged configuration to the engaged configuration, wherein the actuator is full enclosed within the elongate body, wherein the actuator comprises a first ramped surface that is slideably coupled to an interior surface of the bendable member of the gripper, wherein proximally moving the first ramped surface of the actuator causes the first ramped surface to slideably engage the interior surface of said bendable member at an angle thereby pivoting the bendable member of the gripper away from the longitudinal axis away from the elongate body to deploy the bone engaging mechanism into the engaged configuration.

2. The segmented bone fixation device ofclaim 1 wherein a gap between adjacent segments has a gap thickness that is disposed at least partially around the circumference of the elongate body, and wherein the elongate body changes from its flexible state to its rigid state when the gap thickness is reduced through relative motion the adjacent segments.

3. The segmented bone fixation device ofclaim 1, further comprising a flexible-to-rigid body sleeve configured for placement over the flexible-to-rigid body portion.

4. The segmented bone fixation device ofclaim 3, wherein the flexible-to-rigid body sleeve is configured to cover at least one segment, cut, edge, inter-digitation, or gap, of the flexible-to-rigid body portion.

5. The segmented bone fixation device ofclaim 3, wherein the flexible-to-rigid body sleeve is configured to contain at least one segment, cut, edge, inter-digitation, or gap, of the flexible-to-rigid body portion.

6. The segmented bone fixation device ofclaim 1 wherein the actuator is operably connected to the elongate body to change the elongate body from its flexible state to its rigid state.

7. The segmented bone fixation device ofclaim 1, the elongate body further comprising a drive member positioned proximally to the flexible-to-rigid portion of the elongate body and threadably engaged with the actuator.

8. The segmented bone fixation device ofclaim 7 wherein the actuator, having a first interface surface, is disposed at least partially within the flexible-to-rigid portion of the elongate body such that the first interface surface is distal to the flexible-to-rigid portion of the elongate body.

9. The segmented bone fixation device ofclaim 8, wherein by rotating the drive member, the first interface surface of the actuator and the drive member are drawn together thereby applying a compressive force to at least a portion of the elongate body along the longitudinal axis changing the elongate body from its flexible state to its rigid state.

10. The segmented bone fixation device ofclaim 1 wherein the elongate body changes from its flexible state to its rigid state when a compressive force is applied to at least a portion of the elongate body along the longitudinal axis.

11. A segmented bone fixation device comprising:

a generally tubular body having a circumferential surface, an inner lumen, and a wall extending therebetween, the body being sized to fit within an intramedullary space within a bone, the body having a longitudinal axis;

a plurality of individual segments interlinked around the circumferential surface and axially along at least a portion of the body;

a compression mechanism configured to apply an axial compression to the body to move the plurality of individual segments towards a closed position, thereby transforming the body from a generally flexible state to a generally rigid state;

at least one radially expandable gripper disposed within the body for engaging a surface of the intramedullary space; and

an actuator comprising a distal actuator head, wherein the distal actuator head is fully circumferentially enclosed within the tubular body, the distal actuator head comprising a ramped surface slideably disposed on an interior of the at least one radially expandable gripper, the actuator configured to outwardly actuate the at least one radially expandable gripper away from the longitudinal axis and away from the body.

12. The bone fixation device ofclaim 11 further comprising at least one pair of mating features formed by the plurality of individual segments, wherein one of the mating features is located on one side of a first segment and the other mating feature is located on a corresponding side of a second segment.

13. The bone fixation device ofclaim 12 wherein the mating features of at least one of the pairs interlock to limit axial expansion and contraction of the body, and to limit axial rotation in both directions of one part of the body relative to another.

14. The bone fixation device ofclaim 12 wherein the mating features comprise a T-shaped protuberance extending from the first segment into a mating T-shaped cavity in the second segment.

15. The bone fixation device ofclaim 11 wherein a gap between the first segment and the second segment has a width that varies as it extends around the circumferential surface such that one portion of the body may axially compress more than another portion when the plurality of segments moves toward the closed position.

16. The bone fixation device ofclaim 11 further comprising a flexible-to-rigid body sleeve configured for placement over the plurality of individual segments.

17. The bone fixation device ofclaim 11 further comprising at least one screw hole extending radially at least partially through the body for receiving a bone screw to assist in securing the body within the intramedullary space.

18. A method of repairing a bone fracture comprising:

providing an elongate fixation device having a longitudinal axis and at least a portion transformable between a generally flexible state and a generally rigid state, the transformable portion having a plurality of segments;

inserting the device in the generally flexible state into an intramedullary canal of the bone across the fracture;

actuating a compression mechanism on the device to move the plurality of segments towards a closed position, thereby transforming the device portion from the generally flexible state to the generally rigid state;

extending a radially expandable gripper disposed within the elongate fixation device away from the longitudinal axis by moving an actuator along the longitudinal axis, the actuator comprising a distal actuator head with a ramped surface slideably disposed on an interior of the radially expandable gripper, wherein the distal actuator head is fully circumferentially enclosed within the radially expandable gripper; and

engaging the radially expandable gripper to a surface of the intramedullary canal.

19. The method ofclaim 18 wherein the plurality of segments comprises a plurality of pairs of mating features interlocking the segments.

20. The method ofclaim 19 wherein the mating features of at least one of the pairs interlock to limit axial expansion and contraction of the transformable portion, and to limit axial rotation in both directions of one part of the transformable portion relative to another.

21. The method ofclaim 18 wherein the actuating step causes the portion transformable between the generally flexible state and the generally rigid state to change from a first shape to a second shape, the second shape enabling the device to grip at least one bone surface within the intramedullary space.

22. The method ofclaim 18 further comprising extending the radially expanding gripper after the inserting step.

23. The method ofclaim 22 wherein the actuation of the compression mechanism and the extending of the gripper are accomplished in a single step.

24. The method ofclaim 18 further comprising reversing the compression mechanism to transform the device portion from the generally rigid state to the generally flexible state, and removing the device from the bone.

25. The method ofclaim 18, further comprising containing at least a portion of the plurality of segments with a sleeve.

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